DELHI PUBLIC SCHOOL TAPI CLASS X

SUMMATIVE ASSESSMENT 1

SUBJECT: GEN. SCIENCE

CODE: 086

DATE: 30/09/14 TOTAL MARKS: 90

DURATION: Reading – 15 Mins. + Writing – 2 Hr. 45 Mins. + Revision – 15 Mins.

1    

General Instructions: (i) The question paper comprises of two sections, A and B. You are to attempt both the

sections. (ii) All questions are compulsory. (iii) There is no overall choice. (iv) All questions of Section-A and all questions of Section-B are to be attempted

separately. (v) Question numbers 1 to 3 in Section-A are one mark questions. These are to be

answered in one word or in one sentence. (vi) Question numbers 4 to 6 in Section-A are two marks questions. These are to be

answered in about 30 words each. (vii) Question numbers 7 to 18 in Section-A are three marks questions. These are to be

answered in about 50 words each. (viii) Question numbers 19 to 24 in Section-A are five marks questions. These are to be

answered in about 70 words each. (ix) Question numbers 25 to 36 in Section-B are practical based questions (PBQs). Question

numbers 25 to 33 are MCQs carrying one mark each. You are to choose one most appropriate response out of the four provided to you. Question numbers 34 to 36 are short answer type questions carrying two marks each.

SECTION-A

1. What happens when hydrogen combines with oxygen in the presence of an electric current?

2. Why are endocrine glands called ductless glands?

3. The cost of production of electricity in a thermal power station located in Bihar / Jharkhand /

Orissa is lesser than in Gujarat / Maharashtra. Do you agree? Justify your answer.

4. A gas produced in the laboratory is highly soluble in water. Its colourless solution turns pink

when a few drops of phenolphthalein is added to it. What is the nature of this gas?

5. You are given several identical resistors each having resistance of 10 Ω and a maximum current

of 1 A is allowed to pass through each resistor. It is required to make a suitable combination of

these resistances of 5 Ω which can carry a curent of 4 A. Find the number of such resistances

which will be required.

6. Why is the inner wall of alimentary canal not digested although the digestive enzyme can digest

all the materials that make cells?

 

2    

7. The following diagram displays a chemical reaction. Observe carefully and answer the following

questions:

a. Identify the type of chemical reaction that will take place and define it. How will the colour

of the silver chloride change?

b. Write the chemical equation of the reaction that takes place.

c. Mention one commercial use of silver chloride.

8. A magnesium ribbon is burnt in oxygen to give a white compound X accompanied by emission

of light. If the burning ribbon is now placed in an atmosphere of nitrogen, it continues to burn

and forms a compound Y.

a. Write the chemical formula of X and Y.

b. Write a balanced chemical equation, when X is dissolved in water.

9. Think you are sitting in a chamber with your back to one wall. An electron beam, moving

horizontally from back wall towards the front wall, is deflected by a strong magnetic field to

your right side. What is the direction of magnetic field? Explain it diagrammatically.

10. Under what conditions permanent electromagnet is obtained if a current carrying solenoid is

used? Support your answer with the help of a labelled circuit diagram.

11. How are the wastes produced in nuclear power plants different from those produced in thermal

power plants? What happens to the waste of a nuclear power plant?

12. Mention why is it not possible to make use of solar cells to meet all our energy needs? State

three reasons to support your answer. Also mention three uses of solar cells.

13. Ramsingh is a villager who uses underground water for drinking. Fluoride ion, iron levels,

salinity and arsenic levels are high in ground water. Underground water also contains

microorganism which cause diseases like typhoid, cholera. His son Himanshu advised his father

to use boiled water and add one tablet of bleaching powder to one bucket of water.

a. What are harmful effects of F- in water?

b. What can we do for preservation of underground water?

c. What values are possessed by Himanshu?

14. Nervous and hormonal system together perform the function of control and coordination in

human beings. Justify the statement.

15. Find the equivalent resistance across the two ends A and B of this circuit.

 

3    

16. Several electric bulbs designed to be used on a 220 V electric supply line, are rated 10 W. How

many lamps can be connected in parallel with each other across the two wires of 220 V line if

the maximum allowed curent is 5 A?

17. A metal ‘X’ loses two electrons and a non-metal ‘Y’ gains one electron. Show the electron-dot

structure of compound formed between them. Is it ionic or covalent? Does it have high melting

point or low? Will it conduct electricity in solid state or in aqueous solution and why? Will it be

soluble in water?

18. An element A reacts with water to form a compound B which is used in white washing. The

compound B on heating forms an oxide C which on treatment with water gives back B. Identify

A, B and C and give the reactions involved.

19. Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their

structure and functioning.

20. What is endocrine system? What are its functions? Name the important endocrine glands present

in a human body. Draw a labelled diagram to show the positions of these endocrine glands in the

human body (male/female).

21. Two orse A and B were taken. On heating, ore A gives CO2 whereas, ore B gives SO2. What

steps will you take to convert them into metals?

22. A. Crystals of a substance changed their colour on heating in a closed test tube but regained it

after sometime when they were allowed to cool down. Name the substance and write its formula

and explain the phenomenon involved.

B. Name the compound whose one formula unit is associated with 10 water molecules. How is

it prepared? Give equations of related reactions. Give two uses of the compound.

23. Deduce the expression for the equivalent resistance of the parallel combination of three resistors

R1, R2 and R3. Consider the following electric circuit.

24. A student fixes a sheet of white paper on a drawing board. He places a bar magnet at the centre

of it. He spreinkles some iron filings uniformly around the bar magnet. Then he taps the board

gently and observes that the iron filings arrange themselves in a particular pattern.

 

4    

a. Why do the iron filings arrange in a pattern?

b. What is indicated by the crowding of iron filings at the end of the magnet?

c. What do the lines along which the iron filings align represent?

d. Draw a neat diagram to show the magnetic field lines around a bar magnet.

e. Write any two properties of magnetic field lines.

SECTION B

25. Aluminium sulphate and copper sulphate solutions were taken in two test tubes I and II

respectively. A few pieces of iron filings were then added to both the solutions. The four

students A, B, C and D recorded their observations in the form of a table as given below:

Student Al2(SO4)3 Solution (I) CuSO4 Solution (II)

A Colourless solution changes to light

green

Blue colour of the solution is retained

B Colour of the colourless solution

does not change.

Blue colour of the solution changes to

green

C Colourless solution changes to light

blue

Blue colour of the solution changes to

green

D Colour of the colourless solution

remains unchanged

Blue colour of the solution fades away

The correct set of observations has been recorded by student:

a. A b. B c. C d. D

26. During the experiment of heating of ferrous sulphate crystals, four students recorded their

observations as:

(i) green colour of crystals changes to brown black colour

(ii) brownish yellow gas is evolved

(iii) blue colour of crystals changes to green colour

(iv) smell of burning sulphur is felt

Which of the above observations are correct?

a. (i), (ii) b. (i), (iv) c. (ii), (iii) d. (iii), (iv)

 

5    

27. The figure below shows set ups for studying the reaction of zinc with sodium hydroxide.

The correct set up is:

a. I b. II c. III d. IV

28. To determine the equivalent resistance of a series combination of two resistors R1 and R2, a

student arranges the following set up:

Which of the following will be true for this circuit? It gives

a. incorrect reading for current I as well as potential difference V.

b. correct reading for current I but incorrect reading for potential difference V.

c. correct reading for potential difference V but incorrect reading for current I.

d. correct readings for both I and V.

29. A student has to connect 4 cells of 1.5 V each to form a battery of 6 V. The correct way of

connecting these cells is shown in figure:

a. A b. B c. C d. D

 

6    

30. In a voltmeter, there are 20 divisions between the 0 mark and 1 mark. The peast count of the

voltmeter is

a. 20 V b. 5.0 V c. 0.05 V d. 0.025 V

31. Four students focussed an epidermal peel of leaf under high power and made the following

sketches. Which one of the following is sketched correctly?

a. A b. B c. C d. D

32. Given below are randomly written steps for the experiments to show that light is necessary for

photosynthesis. Which one of the following is the correct sequence of steps for a successful run

of the experiment?

I. Pluck the experimental leaf.

II. Using strips of black paper, cover a portion of the leaf on both sides.

III. De-starch leaf of the potted plant.

IV. Test the experimental leaf for presence of starch.

V. Expose the plant to sunlight for four hours.

VI. Remove the black paper strips from the leaf.

a. I, III, II, IV, V, VI

b. II, I, V, VI, III, IV

c. III, II, V, I, VI, IV

d. V, I, II, III, IV, VI

33. Using the same number of given germinating gram seeds, two students A and B conduct the

experiment separately. Student A used a cotton plug to hold the bent tube in the mouth of the

flask. Student B used a rubber cork.

 

7    

After 4 hours, they noticed that

a. water level increased in the bent tube only of A.

b. water level increased in the bent tube only of B.

c. the cotton plug was wet.

d. The water in the beaker of tube turned milky.

34. A solution ‘X’ gives orange colour when a drop of universal indicator is added to it. On the other

hand, another solution ‘Y’ gives bluish-green colour when a drop of universal indicator is added

to it.

What are the types of solution ‘X’ and ‘Y’ and what type of pH would they have?

35. To determine the equivalent resistance of two resistors R1 and R2 when connected in parallel, a

student chooses the resistors to perform the experiment in such a way that R1 > R2. After taking

observations, he plots the V-I graph for the same. Draw the same V-I graph as he plotted by

taking ‘V’ on Y-axis and ‘I’ on X-axis for

(i) R1 and R2, and

(ii) R1 and R2, and their equivalent resistance on the same axis.

36. Why are germinating seeds taken in the experiment? What would happen if germinating seeds

are replaced by boiled seeds?

 

**********************