cbse 10th chemical reactions and equations unsolved...

Perfect solution to all problems

Tips, Tricks, General Knowledge, Current Affairs, Latest Sample,

Previous Year, Practice Papers with solutions.

CBSE 10th Chemical reactions and Equations

Unsolved Paper

Click Button Below To Buy Solution

BUY NOW WITH PayUmoney

Only ₹ 25 OR

Call us on 9557655662 for Paytm or UPI / NEFT payment

Note

This pdf file is downloaded from www.4ono.com. Editing the content or publicizing this on any blog or

website without the written permission of Rewire Media is punishable, the suffering will be decided

under DMCA

https://www.payumoney.com/paybypayumoney/#/374661

http://www.4ono.com/

http://www.rewire.media/

4ono.com 4ono.com 4ono.com 4ono.com 4ono.com 4ono.com 4ono.com 4ono.com 4ono.com 4ono.com 4ono.com 4ono.com 4ono.com

com CBSE 10th Chemical reactions and Equations

Unsolved Paper

_________________________________________________________________________

SECTION - A

Q.1. What happens when dilute hydrochloric acid is added to iron filling? Tick the correct

answer

(a) Hydrogen gas and iron chloride are produced.

(b) Chlorine gas and iron hydroxide are produced

(c) No reaction takes place

(d) Iron salt and water are produced

Q.2. Which of the following is not a balanced equation?

(𝒂) 𝑭𝒆 + 𝑪𝒍𝟐 → 𝑭𝒆𝑪𝒍𝟐

(𝒃)𝑴𝒈 + 𝑪𝒖𝑺𝑶𝟒 → 𝑴𝒈𝑺𝑶𝟒 + 𝑪𝟒

(𝒄)𝑵𝒂𝑶𝑯 + 𝑯𝑪𝑳 → 𝑵𝒂𝑪𝒍 + 𝑯𝟐𝑶

(𝒅)𝒁𝒏 + 𝑺 → 𝑭𝒆𝑪𝒍𝟑

Q.3. Dissolving suger is an example of-

(a) Physical change

(b) Chemical change

(c) Redox Reaction

(d) None of these.

Q.4. Take about 5 ml of dil. HCl in a test tube and add a few pieces of fine granules to it.

Which gas is evolved?

(a) Chlorine

(b) Hydrogen

(c) HCl

(d) Nitrogen

Download More @ www.4ono.com



Q.5. A substance which oxidizes itself and reduces other is known as

(a) Oxidising agent

(b) reducing agent

(c) Both (a) and (b)

(d) None of these.

Q.6. In the reaction 𝑷𝒃𝑶 + 𝑪 → 𝑷𝒃 + 𝑪𝑶

(a) Pbo is oxidised

(b) C act as an oxidising agent

(c) C act as a reduction agent

(d) Reaction does not represent redox reaction.

Q.7. Copper displaces which of the following metals from its salt solution:

(𝒂)𝒁𝒏𝑺𝑶𝟒

(𝒃) 𝑭𝒆𝑺𝑶𝟒

(𝒄) 𝑨𝒈𝑵𝑶𝟑

(𝒅) 𝑵𝒊𝑺𝑶𝟒

Q.8. Which of the following reactions is not correct

(𝒂)𝒁𝒏 + 𝑪𝒖𝑺𝒐𝟒 → 𝒁𝒏𝑺𝑶𝟒 + 𝑪𝒖

(𝒃) 𝟐𝑨𝒈 + 𝑪𝒖(𝑵𝑶𝟑) → 𝟐𝑨𝒈𝑵𝑶𝟑 + 𝑪𝒖

(𝒄) 𝑭𝒆 + 𝑪𝒖𝑺𝑶𝟒 → 𝑭𝒆𝑺𝑶𝟒 + 𝑪𝒖

(𝒅)𝑴𝒈 + 𝟐𝑯𝑪𝒍 → 𝑴𝒈𝑪𝒍𝟐 + 𝑯𝟐

Q.9. PbS reacts with ozone (O3 ) and forms pbso4 . As per the balanced equation,

molecules of ozone required for every one molecule of PbS is / are

(a) 4

(b) 3

(c) 2

(d) 1




Q.10. Some crystals of copper sulphate were dissolved in water. The colour of the solution

obtained would be

(a) green

(b) red

(c) blue

(d) brown.

Q.11. A shiny brown coloured element ‘X’ on heating in air becomes black in colour. Name

the element ‘X’ and the black coloured compound formed.

Q.12.What do you mean by a precipitation reaction? Explain by giving examples.

Q.13. In refining of silver, the recovery of silver from silver nitrate solution involved

displacement by copper metal. Write down the reaction involved.

Q.14. Which of the following statement about the reaction below are incorrect?

𝟐𝑷𝒃𝑶 (𝒔) + 𝑪 (𝒔)𝟐𝑷𝒃 (𝒔) + 𝑪𝑶𝟐 (𝒈)

(a) Lead is getting reduced.

(b) Carbon dioxide is getting oxidized

(c) Lead oxide is getting oxidized

(d) Lead is getting reduced

i. (a) and (b)

ii. (a) and (c)

iii. (a), (b) and (c)

iv. All

Q.15. A solution of a substance ‘X’ is used for white washing

i. Name the substance ‘X’ and writes its formula.

ii. Write the reaction of the substance ‘X’ named in (i) above with water

Q.16. A student burnt a metal A found in the form of ribbon. The ribbon burnt with a

dazzling Flame & a white powder B is formed which is basic in nature. Identify A &

B Write the Balanced chemical equation.




Q.17. A substance X used for coating iron articles is added to a blue solution of a reddish

brown metal Y,the color of the solution gets discharged Identify X and Y & also the

type of reaction.

Q.18. Why respiration is considered an exothermic reaction? Explain.

Q.19. What is balanced chemical equation? Why should chemical equation be balanced?

Q.21. Write the balance equation for the following reactions Give reasons for the following

reactions?

𝒊. 𝑯𝒚𝒅𝒓𝒐𝒈𝒆𝒏 + 𝑪𝒉𝒍𝒐𝒓𝒊𝒏𝒆 → 𝑯𝒚𝒅𝒓𝒐𝒈𝒆𝒏 𝒄𝒉𝒍𝒐𝒓𝒊𝒅𝒆

𝒊𝒊. 𝑩𝒂𝒓𝒊𝒖𝒎 𝒄𝒉𝒍𝒐𝒓𝒊𝒅𝒆 + 𝑨𝒍𝒖𝒎𝒊𝒏𝒊𝒖𝒎 𝒔𝒖𝒍𝒑𝒉𝒂𝒕𝒆

→ 𝑩𝒂𝒓𝒊𝒖𝒎 𝒔𝒖𝒍𝒑𝒉𝒂𝒕𝒆 + 𝑨𝒍𝒖𝒎𝒊𝒏𝒊𝒖𝒎 𝒄𝒉𝒍𝒐𝒓𝒊𝒅𝒆

𝒊𝒊𝒊. 𝑺𝒐𝒅𝒊𝒖𝒎 + 𝒘𝒂𝒕𝒆𝒓 → 𝑺𝒐𝒅𝒊𝒖𝒎 𝒉𝒚𝒅𝒓𝒐𝒙𝒊𝒅𝒆 + 𝒘𝒂𝒕𝒆𝒓

Q.22. Astha has been collecting silver coins and copper coins. One day she observed a black

Coating on silver coins and a green coating on conner coins. Which chemical

phenomenon is responsible for these coatings? Write the chemical name of black and

green coatings?

Q.23. Name the type of reaction seen in the diagram below. Write the reaction for the

Same.

Q.24. Transfer the following into chemical equations and balance them.

(i) Hydrogen gas combines with nitrogen to from ammonia.

(ii) Hydrogen sulphide gas burns in air to give water and sulphurdioxide.

(iii) Potassium metal reacts with water to give potassium hydroxide and hydrogen

gas.

Q.25. Explain the following terms with one example each.

a. Corrosion

b. Rancidity.




Q.26. Explain the following in terms of gain and loss of oxygen with two examples each?

a. Oxidation

b. Reduction

Q.27. What is difference between displacement and double displacement reactions? Write

equations for these reactions.

Q.28. What does one mean by exothermic and endothermic reactions? Give examples.

Q.29. Write the balanced chemical equation for the following and identify the type of

reaction in each case.

(𝒂) 𝑷𝒐𝒕𝒂𝒔𝒔𝒊𝒖𝒎 𝒃𝒓𝒐𝒎𝒊𝒅𝒆 (𝒔) + 𝑩𝒂𝒓𝒊𝒖𝒎 𝒊𝒐𝒅𝒊𝒅𝒆 (𝒂𝒒)

→ 𝑷𝒐𝒕𝒂𝒔𝒔𝒊𝒖𝒎 𝒊𝒐𝒅𝒊𝒅𝒆 (𝒂𝒒) + 𝑩𝒂𝒓𝒊𝒖𝒎 𝒃𝒓𝒐𝒎𝒊𝒅𝒆(𝒔)

(𝒃) 𝒁𝒊𝒏𝒄 𝒄𝒂𝒓𝒃𝒐𝒏𝒂𝒕𝒆 (𝒔) → 𝒁𝒊𝒏𝒄 𝒐𝒙𝒊𝒅𝒆 (𝒔) + 𝑪𝒂𝒓𝒃𝒐𝒏 𝒅𝒊𝒐𝒙𝒊𝒅𝒆 (𝒈)

(𝒄) 𝑯𝒚𝒅𝒓𝒐𝒈𝒆𝒏 (𝒈) + 𝑪𝒉𝒍𝒐𝒓𝒊𝒏𝒆 (𝒈) → 𝑯𝒚𝒅𝒓𝒐𝒈𝒆𝒏 𝒄𝒉𝒍𝒐𝒓𝒊𝒅𝒆 (𝒈)

(𝒅) 𝑴𝒂𝒈𝒏𝒆𝒔𝒊𝒖𝒎 (𝒔) + 𝑯𝒚𝒅𝒓𝒐𝒄𝒉𝒍𝒐𝒓𝒊𝒄 𝒂𝒄𝒊𝒅 (𝒂𝒒)

→ 𝑴𝒂𝒈𝒏𝒆𝒔𝒊𝒖𝒎 𝒄𝒉𝒍𝒐𝒓𝒊𝒅𝒆 (𝒂𝒒) + 𝑯𝒚𝒅𝒓𝒐𝒈𝒆𝒏 (𝒈)

Q.30. Write the balanced chemical equations for the following reactions.

(𝒂) 𝑪𝒂𝒍𝒄𝒊𝒖𝒎 𝒉𝒚𝒅𝒓𝒐𝒙𝒊𝒅𝒆 + 𝑪𝒂𝒓𝒃𝒐𝒏 𝒅𝒊𝒐𝒙𝒊𝒅𝒆

→ 𝑪𝒂𝒍𝒄𝒊𝒖𝒎 𝒄𝒂𝒓𝒃𝒐𝒏𝒂𝒕𝒆 + 𝑾𝒂𝒕𝒆𝒓

(𝒃) 𝒁𝒊𝒏𝒄 + 𝑺𝒊𝒍𝒗𝒆𝒓 𝒏𝒊𝒕𝒓𝒂𝒕𝒆 → 𝒁𝒊𝒏𝒄 𝒏𝒊𝒕𝒓𝒂𝒕𝒆 + 𝑺𝒊𝒍𝒗𝒆𝒓

(𝒄) 𝑨𝒍𝒖𝒎𝒊𝒏𝒖𝒎 + 𝑪𝒐𝒑𝒑𝒆𝒓 𝒄𝒉𝒍𝒐𝒓𝒊𝒅𝒆 → 𝑨𝒍𝒖𝒎𝒊𝒏𝒖𝒎 𝒄𝒉𝒍𝒐𝒓𝒊𝒅𝒆 + 𝑪𝒐𝒑𝒑𝒆𝒓

(𝒅) 𝑩𝒂𝒓𝒊𝒖𝒎 𝒄𝒉𝒍𝒐𝒓𝒊𝒅𝒆 + 𝑷𝒐𝒕𝒂𝒔𝒔𝒊𝒖𝒎 𝒔𝒖𝒍𝒑𝒉𝒂𝒕𝒆

→ 𝑩𝒂𝒓𝒊𝒖𝒎 𝒔𝒖𝒍𝒑𝒉𝒂𝒕𝒆 + 𝒑𝒐𝒕𝒂𝒔𝒔𝒊𝒖𝒎 𝒄𝒉𝒍𝒐𝒓𝒊𝒅𝒆






Only ₹ 25 OR








CBSE 10th Acid Bases and Salts

Unsolved Paper



Only ₹ 25 OR


Note



under DMCA





com CBSE 10th Acid Bases and Salts

Unsolved Paper

_________________________________________________________________________

SECTION - A

Q.1. which of the following gives 𝐂𝐎𝟐 on heating?

(a) Slaked

(b) Quick lime

(c) Lime stone

(d) Soda ash.

Q.2. which is a base and not alkali?

(a) 𝑵𝒂𝑶𝑯

(b) 𝑲𝑶𝑯

(c) 𝑭𝒆(𝑶𝑯)𝟑

(d) None

Q.3. Plaster of Paris is made from

(a) Lime stone

(b) Slaked Lime

(c) Quick lime

(d) Gypsum

Q.4. An aqueous solution with pH-zero is

(a) Acidic

(b) Alkaline

(c) Neutral

(d) Amphoteric




Q.5. The 𝑯+ ion concentration of a solution is 𝟏. 𝟎 × 𝟏𝟎−𝟓𝒎. The solution is

(a) Acidic

(b) Alkaline

(c) Neutral

(d) Amphoteric

Q.6. The difference of water molecules is gypsum and Plaster of Paris is

(a) 𝟓

𝟐

(b) 2

(c) 𝟏

𝟐

(d) 𝟑

𝟐

Q.7. Setting of Plaster of Paris takes place due to

(a) Oxidation

(b) Reduction

(c) Dehydration

(d) Hydration

Q.8. The odour of acetic acid resembles that of

(a) Rose

(b) Burning Plastic

(c) Vinegar

(d) Kerosene

Q.9. Plaster of Paris hardens by

(a) Giving off 𝑪𝑶𝟐

(b)Changing into 𝑪𝒂𝑪𝑶𝟑

(c) Combining with water

(d) Giving out water




Q.10. A drop of liquid sample was put on the pH paper, paper turned blue. The liquid

sample must be of

(a) Lemon Juice

|(b) HCl

(c) Sodium bicarbonate

(d) Ethanoic acid.

SECTION – B

Q.11. What happens to the crystals of washing soda when exposed to air?

Q.12. Why is sodium hydrogen carbonate an essential ingredient is antacids?

Q.13. What is the chemical name of washing soda? Name three raw materials used in

making washing soda by Solvay process?

Q.14. Why should curd and sour substance not be kept in brass and copper vessels.

Q.15. While diluting an acid, why it is recommended that the acid should be added to water

and not water to the acid?

Q.16. Why does distilled water not conduct electricity, whereas rain water does?

Q.17. Why does dry HCl gas not change the colour of the dry litmus paper?




SECTION - C

Q.18. (a) Name the raw materials used is the manufacture of sodium carbonate by Solvay

process?

(b) How is sodium hydrogen carbonate from a mixture of 𝑵𝑯𝟒𝑪𝒍 𝒂𝒏𝒅 𝑵𝒂𝑯𝑪𝑶𝟑?

Q.19. What will you observe when:

(i) Red litmus is introduced into a solution of sodium sulphate.

(ii) Methyl orange is added to dil HCl.

(iii). Blue litmus is introduced into a solution of ferric chloride

Q.20. Explain why?

(a) Common salt becomes sticky during the rainy season.

(b) Blue vittriol change to white upon heating.

Q.21. Metal compound ‘A’ reacts with dilute hydrochloric acid to produce efferenvescence.

The gas evolved extinguishes a burning candle. Write a balanced chemical equation

for the reaction, if one of the compounds formed is calcium chloride.

Q.22. A compound X of sodium is commonly used in kitchen for making crispy pakoras. It

is also used for curing acidity in the stomach. Identify ‘X’. What is its chemical

formula? State the reaction that takes places when it is heated during cooking?

Q.23. Explain why-

(i) Anhydrous calcium chloride is used in desiccators

(ii) If bottle full of concentrated 𝑯𝟐𝑺𝑶𝟒 is left open in the atmosphere by accident,

the acid starts flowing out the bottle of its own.




Q.24. A first aid manual suggests that vinegar should be used to treat wasp sting and

baking soda for bee stings.

(a) What does this information tell you about the chemical name of the wasp sting?

(b) If there were no baking soda in the house, what other house hold substances

would you use to treat as stings?

SECTION – D

Q.25. (a) Why does an aqueous solution of acid conduct electricity?

(b) How does the concentration of hydrogen ions [𝑯𝟑𝑶]+ changes when the solution

of an acid is diluted with water?

(c) Which has higher pH. A concentrated or dilute solution of HCL?

(d) What would you observe on adding dil HCL acid to

(i) Sodium bicarbonate placed in a test tube.

(ii) Zinc metal in a test tube.

Q.26. Compound such as alcohols and glucose also contain hydrogen but are not

categorized as acids. Describe an activity




Q.27. State reason for the following statements:

(i) Tap water conducts electricity whereas distilled water does not.

(ii) Dry hydrogen chloride gas does not turn blue litmus red whereas dilute

hydrochloric acid does.

(iii) During summer season, a milk man usually adds a very small amount of baking

soda to fresh milk.

(iv) For a dilution of acid, acid is added into water and not water into acid.

(v) Ammonia is a base but does not contain hydroxyl group.

Q.28. . A substance ‘X’ used in the kitchen for making tasty crispy pakoras and is also an

Ingredient of antacid. Name the substance ‘X’.

(i) How does ‘X’ help to make cakes and bread soft and spongy.

(ii) Is the pH value of solution of ‘X’ is lesser than or greater than 7.0?

Q.29. Write word equations and then balanced equations for the reaction taking place

when:

(a) Dilute Sulphuric acid reacts with zinc granules.

(b) Dilute hydrochloric acid reacts with magnesium ribbon.

(c) Dilute Sulphuric acid reacts with aluminum powder

(d) Dilute hydrochloric acid reacts with iron fillings.

Q.30. A road tanker carrying an acid was involved in an accident and its contents spilled

on the road. At the side of the road iron drain cover began melting and fizzing as the

acid ran over them. A specialist was called to see if the acid actually leaked into the

nearby river.

(a) Explain why specialist could carry out sample test to see of the river water

contains some acid or not

(b) Suggest a better report name for the word ‘melting’

(c) Explain why the drain covers began fizzing as the acid ran over them.






Only ₹ 25 OR








CBSE 10th Metals and Non-Metals

Unsolved Paper



Only ₹ 25 OR


Note This pdf file is downloaded from www.4ono.com. Editing the content or publicizing this on any blog or


under DMCA





com CBSE 10th Metals and Non-Metals Unsolved

Paper

SECTION-A

Q.1. An iron nail was suspended in 𝑪𝒖𝑺𝑶𝟒 solution and kept for a while the solution is

(a) Remained blue and coating was found on the nail.

(b) turned green and a coating was formed on the nail’

(c) remained blue and no coating was formed on the nail .

(d) turned green and no coating was formed on the nail .

Q.2. The earthy impurities associated with mineral used in metallurgy are called

(a) Slag

(b) Flux

(c) Gangue

(d) Ore

Q.3. Name two metals which are found in nature in the free state.

Q.4. Royal water is prepared by mixing two acids ‘A’ and ‘B’. It can dissolve gold and

platinum. It is highly corrosive and fuming liquid. Identify ‘A’ and ‘B’. What is the

ratio in which ‘A’ and ‘B’ are mixed

Q.5. What is the valency of phosphorus with atomic number 15?

Q.6. Which of the following pairs will give displacement reactions?

(a) NaCl solution and copper metal

(b) 𝑴𝒈𝑪𝒍𝟐 solution and aluminum

(c) 𝑭𝒆𝑺𝑶𝟒 solution and silver metal

(d) 𝑨𝒈𝑵𝑶𝟑 solution and copper

Q.7. A green layer is gradually formed on a copper plate left exposed to air for a week in a

bathroom. What could this green substance be?




Q.8. The correct decreasing order of the metals in the activity series is:

(a) Ca, Mg, Ni, Fe

(b) Ni, Ca, Mg, Fe

(c) Ca, Mg, Fe, Ni

(d) Mg, Ca, Fe, Ni

Q.9. A mineral is known as ore if metal

(a) Cannot be produced from it

(b) Can be produced from it

(c) Can be extracted from it profitably

(d) Is very costly

Q.10. During smelting, an additional substance is added which combines with impurities to

form a fusible product. It is known as

(a) Slag

(b) Mud

(c) Gangue

(d) Flux

SECTION-B

Q.11. Name the following:

(a) A metal, which is preserved in kerosene.

(b) A lustrous coloured non-metal.

(c) A metal, which can melt while kept on palm.

(d) A metal, which is a poor conductor of heat.

12. Explain why calcium metal after reacting with water starts floating on its * surface.

Write the chemical equation for the reaction. Name one more metal

that starts floating after some time when immersed in water.

Q.13. Why do ionic compounds have high melting points?

Q14. Which metals do not corrode easily?

Q.15. .Elements magnesium and oxygen respectively belong to group 2 and group 16 of the

Modern Periodic Table. If the atomic numbers of magnesium and oxygen are 12 and

8 respectively, draw their electronic configurations and show the process of

formation of their compound by transfer of electrons.




Q.16. Why does copper not liberate hydrogen on reaching with dilute sulphuric acid?

Q.17. When a metal X is treated with cold water, it gives a base Y with molecular formula

XOH (Molecular mass = 40) and liberates a gas Z which easily catches fire. Identify

X, Y and Z.

SECTION-C

Q.18. A group of a students looked at different metals and metal sulphate solutions given is

a tabular form From the data, answer the following:

(a) Which metal reacted with all other sulphate solution?

(b) Which metal did not react with any other metal sulphate solution?

(c) Arrange the metals in decreasing order of reactivity

Q.19. What is cinnabar? How is metal extracted from cinnabar? Explain briefly.

Q.20. Arrange the following metals in decreasing order of their reactivity:

(1) Cu, Ca, Mg, Na, Zn

(2) You are provided with three metals: sodium, magnesium and copper, Using only

water as the reactant, how will you identify each of them

(3) Which metal listed in (1) is most likely to occur in the native state?

Q.21. (a)State the electron-dot structure for calcium and sulphur.

(b) Show the formation of CaS by the transfer of electrons.

(c) Name the ions present in this compound CaS. Atomic number of Ca = 20, O = 16.

Q.22. You are given a hammer a battery, a bulb, wires and switch

(a) How could you use them to distinguish between samples of metals and non metals?

(b) Assess the usefulness of these tests to distinguish between metals and non-metals




Q.23. (a) Write the electron dot structures for potassium and chlorine.

(b) Show the formation of KCl by the transfer of electrons.

(c) Name the ions present in the compound, KCl.

Q.24. Define the following terms:

(a) Minerals

(b) Ores

(c) Gangue

SECTION-D

Q.25. (a) An ore on treatment with dilute hydrochloric acid produces brisk effervesces.

What type of ore is this? What steps will be required to obtain metal from the

enriched ore.,

(b) Copper coin is kept immersed in silver nitrate solution for some time. What

change will take place in coin and colour of the solution ? Write balanced

chemical equation of the reaction involve

Q.26. Give reasons:

(a) Platinum, gold and silver are used to make jewellery.

(b) Sodium, potassium and lithium are stored under oil.

(c) Aluminum is highly reactive metal, yet it is used to make utensils for cooking.

(d) Carbonate and sulphides ores are usually converted into oxides during the

process of extraction.

Q.27. How is the method of extraction of metals high up in the reactivity series different

from that for metals in the middle ? Why the same process cannot be applied for

them? Explain giving equations, the extraction of sodium.

Q.28. Hydrogen gas is evolved by reacting a piece of magnesium ribbon with water:

(1) Describe how it could be shown that the gas collected is hydrogen.

(2) Write a chemical equation for the reaction taking place between magnesium and

water using symbols.

(3) Suggest how the appearance of magnesium would change after a week.

(4) A few drops of universal indicator solution were added to water in the beaker.

What colour would expect to see and what pH would this colour indicate?

Q.29. What are alloys? How are they made? Name the constituents and uses of brass,

bronze and solder..




Q.30. Write the names and symbols of two most reactive metals. Explain by drawing

electronic structure how any one of the two metals react with a halogen. State any

four physical properties of the compound formed.



Only ₹ 25 OR






CBSE 10th Carbon Compounds

Unsolved Paper



Only ₹ 25 OR


Note



under DMCA





com CBSE 10th Carbon Compounds

Unsolved Paper

_________________________________________________________________________

SECTION - A

Q.1. While cooking, if the bottom of the vessels is getting blackened on the outside, it means

that

(a) the fuel is not cooked completely.

(b) the fuel is not burning completely.

(c) the fuel is wet.

(d) the is burning completely.

Q.2. Which of the following hydrocarbons undergo addition reactions?

𝑪𝟐𝑯𝟔, 𝑪𝟑𝑯𝟔, 𝑪𝟐𝑯𝟐 𝑨𝒏𝒅𝑪𝑯𝟒

Q. 3. Butanone is a fourcarbon compound with the functional group

(a) carboxylic acid

(b) aldehyde

(c) ketone

(d) alcohol

Q.4. Ethane, with the molecular formula 𝑪𝟐𝑯𝟔 has

(a) 6 covalent bonds

(b) 7 covalent bonds

(c) 8 covalent bonds

(d) 9 covalent bonds

Q.5. Which ions are responsible for making water hard?

Q. 6. Which substance is added for the denaturation of ethyl alcohol




Q.7. IUPAC name of first member of homologous series of ketones is

(a) Ethanone

(b) methanone

(c) Propanone

(d) Butanone

Q. 8. The IUPAC name of 𝑪𝑯𝟑𝑪𝑯𝑶 is

(a) Acetaldehyde

(b) formaldehyde

(c) methyl formaldehyde

(d) ethanol

Q.9. Diamond is not a good conductor of electricity because

(a) It is very hard

(b) Its structure is very compact

(c) It is not soluble in water

(d) It has no free electrons to conduct electric current.

Q.10. The odour of acetic acid resembles that of

(a) Rose

(b) Burning Plastic

(c) Vinegar

(d) Kerosene

SECTION - B

Q.11. ‘A’ compound works well with hard water. It is used for making shampoos &

products for cleaning clothes. A is not 100% biodegradable and causes water

pollution. ‘B’ does not work well with hard water. It is 100% biodegradable and

does not create water pollution. Identify A & B.




Q.12. An organic compound P with molecular formula C2H6Ois an active ingredient of all

alcoholic drinks. It is also used in medicines such as tincture iodine, cough syTups.

1dentif ‘P’. Drop a small piece of sodium into the test tube containing ‘P’.A new

compound ‘Q’ is formed with the evaluation of colorless and odorless gas Name the

gas evolved and compound ‘Q’ write the chemical reaction.

Q. 13. Give a test that can be used to differentiate chemically between butter and cooking

oil?

Q. 14. Explain the nature of the covalent bond using the bond formation in .

Q.15. People use a variety of methods to wash clothes. Usually after adding the soap, they

beat the clothes on stone, or beat it with a paddle, scrub with a brush or the mixture

is agitated in a washing machine. Why is agitation necessary to get clean clothes?

Q.16. What are two properties of carbon which lead to the huge number of carbon

compounds we see around us?

Q.17. What would be the electron dot structure of a molecule of sulphur which is made up

of eight atoms of sulphur?

Q. 18. Two compounds ‘X’ and ‘Y’ have the same formula C One of them reacts with

sodium metal to liberate 112 and CO with NaHCO Second one does not reacts with

Na metal and NaHCO but undergo hydrolysis with NaOH to form salt of carboxylic

acid and compound ‘Z’ which is called wood spirit. Identify ‘X’, ‘Y’, and ‘Z’ and

write chemical equation for the reaction involved.

Q. 19. A cyclic compound ‘X’ has molecular formula . 𝑪𝟔𝑯𝟔 It is unsaturated and burns

with sooty flame. Identify ‘X’ and write its structural formula. Will it decolonze

bromine water or not and why?




Q.20. ‘A’ compound works well with hard water. It is used for making shampoos

&products for cleaning clothes. A is not 100% biodegradable and causes water

pollution. ‘B’ does not work well with hard water. It is 100% biodegradable and

does not create water pollution. Identify A & B.

Q.21. Explain in mechanism of the cleaning action of soap.

Q.22. Why are carbon and its compounds used as fuels for most applications?

Q.23. How can ethanol and Ethanoic acid be differentiated on the basis of their physical

and chemical properties?

Q.24. Given a chemical test to distinguish between

(i) Ethane and ethane

(ii) Ethanol and ethanoic acid

(iii) Soaps and Detergents

SECTION - D

Q.25. (a) Name the gas evolved during fermentation process?

(b) What role is played by yeast in the conversion of cane sugar to ethanol?

(c) How may the following be obtained from pure ethanol? Express (𝑪𝟏𝟐𝑯𝟏𝟐𝑶𝟏𝟏 )

s chemical reactions by the chemical equations.

(i) Sodium ethoxide

(ii) Ethyl ethanoate

(iii) Ethanal




Q.26. Define fermentation. Name the enzyme which converts

(a) milk into curd (yogurt)

(b) Cane sugar into glucose and fructose

(c) glucose into ethanol

Q.27. (a) Why does carbon form largest number of compounds?

(b) Why are some of these called saturated and other unsaturated compounds?

(c) Which of these two is more reactive?

(d) Write the names of the following compounds

(I) 𝑪𝑯𝟐 − 𝑪𝑯𝟐 − 𝑩𝒓

(II) 𝑪𝑯𝟑 − 𝑪𝑯 − 𝑪𝑯 − 𝑪𝑯 − 𝑪 ≡ 𝑪 − 𝑯

Q.28. Draw the structure for the following compounds:

(i) Ethanoic acid

(ii) Bromopentane

(iii) Butane

(iv) Hexanal

Q.29. Why does micelle formation take place when soap is added to water? Will a micelle

be formed in other solvents such as ethanol also?

Q.30. Draw the electron dot structure for

(a) Ethanoic acid

(b) 𝑯𝟐𝑺

(c) Propanone

(d) 𝑭𝟐






Only ₹ 25 OR








CBSE 10th Periodic Classification Of

Elements Unsolved Paper



Only ₹ 25 OR


Note



under DMCA





com CBSE 10th Periodic Classification Of

Elements Unsolved Paper

_________________________________________________________________________

SECTION - A

Q.1. X, Y and Z are the elements of a dobereiners triad. If the atomic mass of x is 7 and

that of z is 39, what should be the atomic mass of y?

Q.2. A and B are the two elements having similar properties which obey Newlands law of

octaves. How many elements are there in between A and B?

Q.3. Which of the following statements is not correct statement about the trends when

going from left to right across the periods of Periodic Table?

(a) The elements become less metallic in nature.

(b) The number of valance electrons increases.

(c) The atoms lose their electrons more easily.

(d) The oxides becomes more acidic.

Q4. Element X forms a chloride with the formula 𝑿𝑪𝒍𝟐which is a solid with a high melting

point. X would most likely be in the same group of the Periodic Table as

(a) Na

(b) Mg

(c) Al

(d) Si

Q.5. Besides gallium, which other elements have since been discovered that were left by

Mendeleev in his Periodic Table?

Q.6. Which of the following is the most reactive halogen?

(a) F

(b) Cl

(c) Br

(d) I




Q.7. The number of periods in the long form of the periodic table is

(a) 6

(b) 7

(c) 10

(d) 18

Q.8. The law of octaves was proposed by

(a) Newland

(b) Doberiener

(c) Lother Meyer

(d) Mendleeve

Q.9. Which of the following has maximum atomic size?

(a) K

(b) Ca

(c) Al

(d) P

Q.10. Name three elements which behave as metalloids?

SECTION - B

Q.11. Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to group 15

of the Periodic Table. Write the electronic configuration of these two elements.

Which of these will be more electronegative? Why?

Q.12. (a) What property do all elements in the same column of the Periodic Table as boron

have in common?

(b) What property do all elements in the same column of the Periodic Table as

Fluorine have common?




Q.13. How could the Modern Periodic table remove various anomalies of Mendeleev’s

Periodic Table?

Q.14. Did Dobereiner’s triads also exist in the columns of Newland’s Octaves? Compare

and find out?

Q.15. Hydrogen is regarded as a rogue element in the periodic table. Discuss.

Q.16. How were the positions of different isotopes decided in the modern periodic table?

Q.17. Alkali metals do not form dipositive ions why?

SECTION – C

Q.18. The diagram below shows part of the Periodic Table

The position of three elements in the Periodic Table is shown:

i Write the atomic numbers of the elements.

ii Give the electronic distribution of the elements iii Using these three elements as

examples, describe the trend in chemical properties across the third period of the

Periodic Table.




Q.19. An element X (2,82) combines separately with NO and (S04)2 -, (P0 -radicals. Write

the formulae of the three compounds so formed. To which group of the periodic table

does the element ‘X’ belong? Will it form covalent or ionic compound? Why?

Q.20. Two elements X and Y have atomic numbers 12 and 16 respectively. Write the

electronic configuration for these elements. To which period of the modem periodic

table do these two elements belong? What type of bond will be formed between them

and why?

Q.21. Which element has

(a) two cells, both of which are completely filled with electrons?

(b) the electronic configuration 2, 8, 2?

(c) a total of three shells, with four electrons in its valance shell?

(d) twice as many electrons in its second shell as in its first shell?

Q.22. (a) Lithium, sodium and potassium are all metals that react with water to liberate

hydrogen gas. Is there any similarity in the atoms of these elements?

(b) Helium is an un-reactive gas and neon is a gas of extremely low reactivity. What,

if anything, do their atoms have in common?

Q.23. Name:

(a) Three elements that have a single electron in their outermost shells.

(b) Two elements that have two electrons in their outermost shells.

(c) Three elements with filled outermost shells.

Q.24. What were the limitations of Newland’s law of octaves?

SECTION – D

Q.25. Calcium is an element with Z = 20

(a) Is it a metal or a non-metal?

(b) Will its size be bigger or smaller than that of potassium?

(c) write the formula of its chloride




Q.27. (a) Name the elements present in the third period and classify them into metals and

non-metals.

(b) On which side of the table do you find the metals?

(c) On which side of the table do you find the non-metals?

Q.28. Write two major shortcomings of Mendeleev’s periodic table? How have these been

removed in the modern periodic table?

Q.29. Two elements X and Y belong to Group 1 and Group 2 respectively in the same

period. Compare them with respect to:

(a) The number of valence electrons

(b) Valency

(c) metallic character

(d) Size of the atoms

(e) Formulae of their oxides and chlorides.

Q.30. What were the limitations of Newland’s law of octaves?



Only ₹ 25 OR








CBSE 10th Life Processes

Unsolved Paper



Only ₹ 25 OR


Note



under DMCA





com CBSE 10th Life Processes Unsolved Paper

_________________________________________________________________________

SECTION - A

Q.1. The breakdown of pyruvate to give carbon dioxide, water and energy takes place in

(a) cytoplas m

(b) mitochondria

(c) chloroplast

(d) nucleus

Q.2. The xylem in plants are responsible for

(a) transport of water

(b) transport of food

(c) transport of amino acids

(d) transport of oxygen

Q.3. Name the part of alimentary canal receiving bile from the liver.

(a) Oesophaggus

(b) Stomach

(c) Small intestine

(d) Large intestine

Q.4. Amoeba captures food with the help of –

(a) teeth

(b) cilia

(c) pseudopodia

(d) tentacles

Q.5. In which of the following group/ groups of animals, heart does not pump oxygenated

blood to different parts of the body?

(a) Pisces only

(b) Amphibians only

(c) Amphibians and reptiles only

(d) Pisces and amphibians.




Q.6. When air is blown from mouth into a test – tube containing lime water, the lime water

turned milky due to presence of –

(a) oxygen

(b) nitrogen

(c) water vapours

(d) carbon – dioxide

Q.7. The autotrophic mode of nutrition requires –

(a) Chlorophyll

(b) Sunlight

(c) Carbon – dioxide & water

(d) all of the above

Q.8. Trachea do not collapse when there is not much air because they are –

(a) thick and muscular

(b) having cartilaginous rings

(c) Have valves

(d) supported by larynx.

Q.9. Which of these is not a part of the small intestine?

a) Duodenum

(b) Jejunum

(c) Ileum

(d) Rectum

Q.10. Give one example each of saprophytic and parasitic nutrition.

SECTION B

Q.11. “If there were no algae there would be no fish in the sea”. Comment.




Q.12. Which of the organs perform the following functions in humans? i. Absorption of

food. ii. Absorption of water

Q.13. Autotrophs synthesis food for the living world. Justify this statement in one sentence

only interconnecting autotrophs and heterotrophs.

Q.14. Why are glomeruli considered as dialysis bags?

Q.15. Name the respiratory organs of (i) fish (ii) mosquito (iii) earthworm.

Q.16. When we are asleep we are not performing any activity still our life processes are

going on. Why?

Q.17. If you compare your rate of breathing by feeling your chest movement with the

number of times a fish opens and closes its mouth. Which will be higher and way?

SECTION - C

Q.18. What are differences between aerobic and anaerobic respiration? Name some

organisms that use anaerobic mode of respiration.

Q.19. What are the necessary conditions for autotrophic nutrition and what are its

byproducts.

Q.20. How is amount of urine produced regulated?

Q.21. What are the components of the transport system in human beings? What are the

functions of these components?




Q.22. How is small intestine deigned to absorb digested

Q.23. Why and how does water enter continuously into the root xylem of plants?

Q. 24. Explain the structure of chloroplast.

SECTION – C

Q.25. With the help of a labelled diagram of human excretory system, Mention its

important part and explain them.

Q.26. What is ‘clotting of blood’? Write a flow chart showing major events taking place in

clotting of blood? Ans. Formation of clot at the site of injury to stop bleeding is

known as ‘clotting of blood’. Steps for clotting of blood –

Q.27. (i) Draw a well labeled diagram of human digestive system

(ii) Describe the role of following in digestion.

a) Bile

b) Salivary amylase

c) HCl




Q.28. Describe an experiment to prove that carbon – dioxide is essential for the process of

photosynthesis.

Q.29. With the help of labeled diagram, Discuss the mechanism of respiration in human

beings.

Q.30. Describe double circulation in human beings. Why is it necessary?



Only ₹ 25 OR








CBSE 10th Control And Co-ordination In

Animals And Plants Unsolved Paper



Only ₹ 25 OR


Note



under DMCA





com CBSE 10th Control And Co-ordination In

Animals And Plants Unsolved Paper

_________________________________________________________________________

SECTION - A

Q.1. Name the plant hormone:

(a) which inhibits growth and causes wilting of leaves.

(b) which promotes cell division.

Q.2. The brain is responsible for

(a) thinking

(b) regulating the heart beat.

(c) balancing the body

(d) all of above

Q.3. The gap between two neuron is called a

(a) Dendrite

(b) synapse

(c) axon

(d) impulse

Q.4. The substance that result into the fall of mature leave and fruits from plants is due to :

(a) auxin

(b) gibberllin

(c) ABA

(d) cytokinin

Q. 5. Which one of the following is a nastic movement in plants?

(a) Bending of plants towards light

(b) Growing of roots towards gravity.

(c) Droping of touch – me – not leaflets on touch

(d) Movement of pollen tubes towards chemicals.




Q.6. The neurons that carry nerve impulse from spinal cord to effectors are called –

(a) Sensory neurons

(b) motor neurons

(c) Inteneurons

(d) spinal neurons

Q.7. Dwarfism results by –

(a) Excess secretion of thyroxin

(b) Less secretion of growth hormone

(c) less secretion of adrenaline

(d) Excess secretion of growth hormone.

Q.8. Which one of the endocrine glands is known as master gland?

(a) Pituitary

(b) Adrenal

(c) Thyroid

(d) Parathyroid

Q.9. The brain is lodged inside the cavity of skull known as :

(a) Piamater

(b) Duramater

(c) Cranium

(d) Meninges

Q.10. Which of the following is a plant hormone?

(a) Insulin

(b) Thyroxin

(c) Oestrogen

(d) Cytokinin




SECTION – B

Q.11. There is a polled plant in your drawing room, after few days you note that plant has

bent to one side. What could be the reason? How has this movement been

coordinated?

Q.12. Why do leaves drop off seasonally?

Q.13. How is the movement of leaves of the sensitive plant different from the movement of

a shoot towards light?

Q.14. Name two activities which are regulated by plant pigments.

Q.15. Name any two heterocrine glands and mention their function.

Q. 16. How following is affected in plants by various hormones?

Q.17. How endocrine glands do helps in maintaining feedback control?

SECTION- C

Q.18. Give a reason to explain why

(a) adrenaline helps in dealing emergency situations?

(b) secretions of growth hormone should be specific in the human body?

Q.19. What is the difference between the manner in which movement’s takes place in a

sensitive plant and movement in our legs?




Q.20. Which signals will get disrupted in case of a spinal cord injury?

Q.21. Design an experiment to demonstrate hydrotropism.

Q.22. Nervous and hormonal system together performs the functions of control and co –

ordination in human beings. Justify the statement.

Q.23. You have touched a hot object. Represent diagrammatically the path that leads to a

response, i.e. quickly pulling back the hand.

Q.24. How does chemical co-ordination takes place in animals. Mention their function.

SECTION – D

Q.25. Draw the structure of a neuron and explain its function.

Q26. Describe Nervous system in humans.

Q.27. Design an experiment to demonstrate hydrotropism.

Q.28. (a) what are hormones?

(b) list four characteristics of hormones

Q.29. Mention one function for each of these hormones.

i) Thyroxine

ii) Insulin

iii) Adrenaline

iv) Growth hormone

v) Testosterone.




Q.30. Compare nervous and hormonal mechanism for control



Only ₹ 25 OR






CBSE 10th How Do Organisms

Reproduce Unsolved Paper



Only ₹ 25 OR


Note



under DMCA





com CBSE 10th How Do Organisms

Reproduce Unsolved Paper

_________________________________________________________________________

SECTION - A

Q.1. In vegetative reproduction, the new individuals are genetically-

(a) Similar

(b) Dissimilar

(c) Abnormal

(d) None of these

Q.2. What is the effect of DNA copying which is not perfectly accurate on the reproduction

process?

Q.3. Which part of the flower forms the fruit?

(a) Whole flower

(b) Only stamens and carpel

(c) Only ovary

(d) Only ovary

Q.4. Define parthenogenesis.

Q.5. Anemophily is the pollination by –

(a) Birds

(b) Rain

(c) insects

(d) Wind

Q.6. Fertilization in plants occurs in the.

(a) Embryo

(b) Style

(c) Pollen tube

(d) Stigma




Q.7. What is tubectomy?

Q.8. Which among the following diseases is not sexually transmitted?

(a) Syphilis

(b) Gonorrhoea

(c) HIV – AIDS

(d) Hepatitis

Q.9 Which of the following is an IUCD?

(a) Copper - T

(b) Diaphragm

(c) oral pills

(d) tubectomy

Q.10. Asexual reproduction takes place through budding in..

(a) Amoeba

(b) Yeast

(c) Plasmodium

(d) Leishmania

SECTION – B

Q.11. What is ‘reproduction’? Mention the importance of DNA copying in reproduction.

Q.12. Name one sexually transmitted disease each caused due to bacterial infection and

viral infection. How can these be prevented?

Q.13. What is callus?

Q.14. Give two examples each of IUCD and STD.

Q.15. What is the difference between binary fission and multiple fission?

Q.16. What are the basic features of asexual reproduction?




Q.17. What is a clone? Why do offspring’s formed by asexual reproduction exhibit

remarkable similarity?

SECTION – C

Q.18. Name the surgical methods of birth control in human males and females respectively.

Q.19. “Variations that confer an advantage to an individual organism only will survive in a

population.” Justify.

Q.20. Mention the events taking place when the ovum is fertilized in fallopian tube till it is

implanted in the uterus of human female.

Q.21. What are the advantages of vegetative propagation?

Q.22. How are spores produced in sporangium of Rhizopus?

Q.23. What is grafting? Why is it used in horticulture practices?

Q.24. Why does menstruation occurs.

SECTION – D

Q.25. Describe triples fusion in plants? Where does it occur? Draw a neat and clean well

labeled diagram to support your answer.

Q.26. Differentiate between asexual and sexual reproduction.




Q.27. Draw a longitudinal section of a flower and label the following parts:

(i) Part that produces pollen grain.

(ii)Part that transfers male gametes to the female gametes.

(iii) Part that is sticky to trap the pollen grain.

(iv) Part that develops into a fruit

Q.28. Explain vegetative propagation with the help of two examples. List two advantages of

vegetative propagation.

Q.29. Explain the following methods of contraception giving one example of each:

(i) Barrier method

(ii) Hormonal imbalance method

(iii) Surgical method.

Q.30. (a) What is fragmentation in organism?

Name a multicell-ular organism which reproduces by this method.

(b) What is regeneration in organism? Describe regeneration in Planaria with the

help of a suitable diagram.






Only ₹ 25 OR








CBSE 10th Heredity And Evolution

Unsolved Paper



Only ₹ 25 OR


Note



under DMCA





com CBSE 10th Heredity And Evolution

Unsolved Paper

_________________________________________________________________________

SECTION - A

Q.1. Two pea plants one with round green seeds (RRyy) and another with wrinkled yellow

(rrYY) seeds produce progeny having round, yellow (RrYy) seeds. When plants are

selfed, the progeny will have the following combination of characters

(a) 15:1

(b) 9:3:3:1

(c) 9:3:4

(d) 12:3:1

Q.2. How many autosome are present in human sperm?

(a) 32

(b) 30

(c) 22

(d) 23

Q.3. Two pink colored flowers on crossing results in 1red, 2pink and 1white flower

progeny. The nature of the cross is-

(a) cross fertilization

(b) self-pollination

(c) double fertilization

(d) no fertilization

Q.4. A basket of vegetable contains carrot, potato, radish, and tomato. Which of them

represent the correct homologous structure.

(a) carrot and potato

(b) carrot and tomato

(c) radish and carrot

(d) radish and potato

Q.5. What is the scientific name of human being?




Q.6. Who is called father of genetics?

Q.7. Genetics is the study of-

(a) resemblances amongst individuals

(b) heredity and environment

(c) differences amongst individuals

(d) Heredity and variations.

Q.8. Wing of a bird and wing of an insect are

(a) Homologous organs

(b) analogous organs

(c) vestigial organ

(d) both (a) and (b)

Q.9 Mendel crossed a pure white recessice pea plant with a dominant pure red flowered

plant. What will be the first generation f hybrids.?

Q.10. Name 2 organisms in which sex determination is regulated by environmental factors.

SECTION – B

Q.11. How does the creation of variations in a species promote survival?

Q.12. How evolution and classification are linked?

Q.13. How do Mendel’s experiments show that traits are inherited independently ?

Q.14. How many contrasting characters did Mendel see in garden pea? Give any two of

them.

Q.15. What are variations? Give their types.




Q.16. Why are the small numbers of surviving tigers a cause of worry from the point of

view of genetics ?

Q.17. Why did Mendel choose pea plant for his experimentation?

SEACTION – C

Q.18. How is the equal genetic contribution of male and female parents ensured in the

progeny?

Q.19.What are the different approaches to determine evolutionary history of man?

Q.20. What are homologous and analogous organ? Explain with the help of example.

Q.21. Only variations that confer an advantage to an individual organism will survive in a

population. Do you agree with this statement ? Why or why not ?

Q.22. What are fossils ? What do they tell us about the process of evolution ?

Q.23. Describe how the sex of the offspring is determined in the zygote ins human beings?

Q.24. What evidence do we have for the origin of life from inanimate matter?

SECTION – D

Q.25 Give the basic features of the mechanism of inheritance.

Q.26. (i) Who provided the evidence of DNA as genetic material?

(ii) Why DNA is called polynucleotide?

(iii) List three important features of double helical model of DNA.




Q.27. What evidence do we have for the origin of life from inanimate matter?

Q.28. Outline a project which alms to find the dominant coat colour in dogs.

Q.29. Explain how sexual reproduction gives rise to more viable variations that asexual

reproduction. How does this affect the evolution of those organisms that reproduce

sexually ?

Q.30. How is the equal genetic contribution of male and female parents ensured in the

progeny?



Only ₹ 25 OR








CBSE 10th Light Reflection And

Refraction Unsolved Paper



Only ₹ 25 OR


Note



under DMCA





com CBSE 10th Light Reflection And Refraction

Unsolved Paper

_________________________________________________________________________

SECTION – A

Q.1. The rays, parallel to the principal axis, of a spherical mirror, actually meet at a point

20 cm distant from its pole. Identify the mirror and give its focal length.

Q.2 Define the principal focus of a concave mirror?

Q.3. Define 1 dioptre of power of lens.

Q.4. The radius of curvature of a spherical mirror is 20 cm. What is its focal length?

Q.5 Find the power of a concave lens of focal length 2 m.

Q.6 Define one dioptre?

Q.7 Find the focal length of a convex mirror whose radius of curvature is 32 cm.

Q.8. A concave mirror produces three times magnified (enlarged) real image of object

placed at 10 cm in front of it. Where is the image located?

Q.9. Focal length of a convex mirror is 10 cm. Find the radius of curvature of the mirror?




Q.10. Which of the following lens would you prefer to use while reading small letters found

in a dictionary?

(a) A convex lens of focal length 50 cm

(b) A concave lens of focal length 50 cm

(c) A convex lens of focal length 5 cm

(d) A concave lens of focal length 5 cm

SECTION – B

Q.11. Find the power of a concave lens of focal length 2 m?

Q.12. Three mirrors, one plane, one concave and one convex are lying on the table. How

can a person identify them without touching them or using any other apparatus or

device?

Q.13. Why do we prefer a convex mirror as a rear view mirror in vehicles?

Q.14. Find the focal length of a convex mirror whose radius of curvature is 32 cm.

Q.15. A concave mirror produces three times magnified real image of an object placed at

10 cm in front of it. Where is the image located?

Q.16. Absolute refractive Index of some of material is tabulated below

Material Rock Salt Kerosene Water Diamond

Refractive 1.54 1.44 1.33 2.42

(i) In which of these does light travel fastest and why?

(ii) arrange these materials in ascending order of their optical densities.




Q.17. A rod of length 10 cm lies along the principal axis of a concave mirror of 10 cm in

such a way that the end closer to the pole is 20 cm away from it. Find the length of

image?

SECTION – C

Q.18. Draw a ray diagram to represent the nature, position and size of the image formed by

a convex lens for the object placed at

(a) infinity

(b) Between 𝑭𝟏 and optical centre (O)

Q. 19. A convex mirror used on a bus has a focal length of 200 cm. If a scooter is located at

100 cm. from this mirror find the position, nature and magnification of the image

formed in the mirror.

Q.20. A concave lens has focal length of 20 cm. At what distance from the lens a 5 cm tall

object be placed so that it forms an image at 15 cm from the lens? Also calculate the

size of the image formed?

Q.21. An object is kept at a distance of 15 cm from a (a) convex mirror (b) concave lens (c)

Plane mirror. The focal length of the convex mirror and the concave lens are 10 cm

each. Draw the appropriate ray diagrams, showing the formation of image, in each of

the three cases.

Q.22. A concave mirror is used to form an erect and enlarged image of a given object.

Where is the image located with respect to the mirror? Draw the corresponding ray

diagram.




Q.23. Light enters from air to glass having refractive index 1.50. What is the speed of light

in glass? The speed of light in vacuum is = 𝟑 × 𝟏𝟎𝟖𝒎/𝒔

Q.24. We wish to obtain an erect image of an object, using a concave mirror of focal length

15 cm.

What should be the range of distance of the object from mirror? What is the nature

of image? Is the image larger or smaller than the object? Draw a ray diagram to

show the image formation in this case.

SECTION – D

Q.25. An object is placed at a distance of 12 cm in front of a concave mirror. It forms a real

image four times larger than the object. Calculate the distance of the image from the

mirror

Q.26. A rod of length 10 cm lies along the principal axis of a concave mirror of 10 cm in

such a way that the end closer to the pole is 20 cm away from it. Find the length of

image?

Q.27. A convex lens of focal length 15 cm forms an image 10 cm from the lens. How far is

the object placed from the lens? Draw the ray diagram.

Q.28. An object 5 cm in length is held 25 cm away from a converging lens of focal length 10

cm. Draw the ray diagram and find the position, size and the nature of the image

formed.

Q.29. One-half of a convex lens is covered with a black paper. Will this lens produce a

complete image of the object? Verify your answers experimentally. Explain your

observations.




Q.30. Draw a ray diagram to show the use of a convex lens for the formation of images

having the following characteristics.

(a) Real & inverted and diminished

(b) Virtual, erect & magnified.



Only ₹ 25 OR








CBSE 10th Human Eye And Colourful

Unsolved Paper



Only ₹ 25 OR


Note



under DMCA





com CBSE 10th Human Eye And Colourful

Unsolved Paper

_________________________________________________________________________

SECTION - A

Q.1. What happens to the image distance in the eye when we increase the distance of an

object from the eye?

Q.2. What is meant by scattering of light?

Q.3. What is the far point and near point of the human eye with normal vision ?

Q.4. Name the muscle responsible for bringing change in the focal length of the eye lens?

Q.5. The human eye forms the image of an object at its

(a) Cornea

(b) Iris

(c) Pupil

(d) Retina

Q.6. The defect of myopia can be corrected by using

(a) Concave lens

(b) Convex lens

(c) Either concave or convex

(d) A complicated combination of lenses.

Q.7. The colour that is scattered the least by the tiny particles and the atoms/ molecules of

the atmosphere is.

(a) Violet

(b) Green

(c) yellow

(d) Red




Q.8. The focal length of the eye lens increases when eye muscles.

(a) are relaxed and lens becomes thinner

(b) contract and lens becomes thicker

(c) are relaxed and lens becomes thicker

(d) Contract and lens becomes thinner.

Q.9. What phenomenon causes twinkling of star on a clear night?

Q.10. Which color has largest wavelength?

SECTION – B

Q.11. The far point of a myopic person is 80 cm in front of the eye. What is the nature and

power of the lens required to correct the problem.

Q.12. If your eye glasses have focal length 60 cm what is your nor point?

Q.13. The far point of a myopic person is 80 cm in front of the eye. What is the nature and

power of the lens required to correct the problem?

Q.14. Name the phenomenon responsible for the observed twinkling of stars. Will this

twinkling be observed by an observer on the moon.

Q.15. A student has difficulty reading the blackboard while sitting in the last row. What

could be the defect the child is suffering from? How can it be corrected?

Q.16. What is the role of the ciliary muscles?

Q.17. What happen to the image distance in the eye when we increase the distance of an

object from the eye?

SECTION – C




Q.18. A person needs a lens of power -5.5 dioptre for correcting his distinct vision. For

correcting his near vision he needs a lens +1.5 dioptre. What is the focal length of the

lens required for correcting (i) distinct vision, and (ii) near vision?

Q.19. Why does the sun appear reddish early in the morning?

Q.20 (a) What is scattering of light?

(b) Astronauts observe the sky as dark instead of blue why?

Q.21. The change in focal length of an eye lens is caused by the action of the

(a) pupil

(b) retina

(c) ciliary muscles

(d) iris

Q.22. What is presbyopia? State the causes of this defect? How is presbyopia of a person

corrected?

Q.23. A reporter records the following observations of an astronaut from his space ship.

(a) The length of the day is same as observed on the earth.

(b) Sky appears black in colour.

(c) The star appears to twinkle while the planets do not do so as they do on the earth.

Justify each statement

Q.24. A certain person has minimum distance of distinct vision of 150cm . He wishes to

read at a distance of 25cm. What focal length glass should he use? What is the nature

of eye defect?

SECTION – D

Q.25. A person needs a lens of power −5.5 dioptres for correcting his distant vision. For

correcting his near vision he needs a lens of power +1.5 dioptre. What is the focal

length of the lens required for correcting (i) distant vision, and (ii) near vision?




Q.26. Make a diagram to show how hypermetropia is corrected. The near point of a

hypermetropic eye ¡s 1 m. What ¡s the power of a lens required to correct this defect?

Assume that near point of the normal eye is 25 cm.

Q.27. A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should

be the type of the corrective lens used to restore proper vision?


hypermetropic eye is 1 m. What is the power of the lens required to correct this

defect? Assume that near point of the normal eye is 25 cm.

Q.29. A 14 year old student is not able to see clearly the questions written of the black

board placed at a distance of 5 m from him.

(a) Name the defect of vision he is suffering from?

(b) Draw the diagram to show this defect?

(c) Name the type of lens used to correct this defect?

(d) Name two possible cause of this defect.

(e) Draw the diagram to show how this defect can be corrected.


hypermetropic eye is 1 m. What is the power of the lens required to correct this

defect? Assume that the near point of the normal eye is 25 cm.



cbse 10th chemical reactions and equations unsolved...

Documents