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CLASS XII B(SCIENCE STREAM)

HOLIDAY ASSIGNMENT 2019-20

“A healthy nation is always a wealthy nation.”

One can think of a healthy mind only in a healthy body. Both physical and mental

well-being are the perquisites of great achievement in man’s life!!

INSTRUCTIONS/GUIDELINES

a) Your full name and class must be written CLEARLY on the folder.

b) Make the folder attractive.

c) Each item must begin on a fresh page.

d) Overall presentation – layout/neatness/grammar/spelling/illustration and

handwritten.

e) Assignments must be submitted on the first day when the school reopens.

f) Compile all the work and submit it in a clear bag.

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ENGLISH

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1. On the occasion of Vana Mahotsava Day , the Environment Club of Greenfield Public

School , Gandhinagar is organizing a Tree Plantation Drive.As the Secretary of the

Club , draft a notice in about 50 words to

Announce the drive and give details like date , time , venue and occasion

Invite all the students to participate in it

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Mention different activities that will be undertaken as part of the drive

2. International Tobacco Control Programme is an organization that is working

worldwide to spread awareness about the hazards of tobacco use. Create a poster

for the organization highlighting the harmful effects of smoking and tobacco

consumption in other forms. Include a helpline number for quitting tobacco and a

website address for more information on quitting smoking / tobacco.

3. A poor accident victim needs financial help for surgery. As the President of a charity

organization that arranges financial help for such parents, draft a classified

advertisement to raise funds for the patient.

In your advertisement you should say

What the patient’s gender , age and financial conditions are

What kind of surgery he/ she needs and its total cost

How much money is needed and how donations can be made

What the organization’s name and contact details are

4. Reckless driving on highways turns roads into death traps for pedestrians and

motorists alike. Write an article in about 200 words on the topic “Reckless Driving

Thrills But Kills.”

In your article you should

Give some examples of accidents on highways to prove they are not safe.

Discuss the causes and consequences of such accidents

Suggest some effective ways to ensure safety on highways.

5. Too much television is bad for children. Unfortunately, parents find it very hard to

wean their children away from the idiot box. Write an article for a local newspaper

to:

Discuss the hazards of viewing too much TV

Explain why it is difficult to wean children away from TV

Suggest what should be done to restrict TV viewing among children

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6. The sports incharge of your school has asked you to make a speech on the value of

games and sports in life in the morning assembly. Draft a speech in about 200 words

in which you should:

Highlight the importance of games and sports as natural instinct of Man

List the benefits of games and sports

Urge young people to practice some sport or the other

7. In recent times there has been a sudden proliferation of tuition and coaching

centres.Are they relevant and useful? Are they a blot on our education system? What

are your views? Draft a speech in about 200 words to ;

Highlight the hardships students have to bear on account of tuitions

Discuss the causes of mushrooming f tuition and coaching centres

Suggest what should be done to curb this menace

8. Due to poor maintenance of the existing system of water supply, the common people

of your city have been hit hard .Write a letter to the Municipal Commissioner of your

City for a permanent solution to this problem. You are Ashutosh Rana, resident of

7/23, Kunal Apartments, Delhi.

In your letter you should:

Introduce yourself and raise the issue of erratic water supply in the city

Describe how much the common and poor people have to suffer due to shortage

of water , while the rich and powerful enjoy unrestricted supply

Suggest some practical steps needed to effectively tackle the problem

Wind up with the hope that the problem will be resolved at the earliest

9. Write a summary of Silas Marner

10. Solve the Mid Term Question paper and all the class tests questions.

All work to be done on A4 sheets and filed. The work should be submitted on the

1st Day of the reopening Day.

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Biology

1. When does a human body elicit an amnestic response?

2. A student on a school picnic to a park on a widy day started sneezing and having

difficulty in breathing on reaching the park. The teacher enquired whether the

student was allergic to something.

a) What is an allergy?

b) Write the two unique characteristics of the system involved in the response

observed in the student.

3. Why do algae and fungi shift to sexual mode of reproduction just before the onset of

adverse conditions?

4. What is plant breeding? List all the steps , the classical plant breeding involves.

5. Why is it difficult to get rid of ‘Water hyacinth’ from a water body? Name one abiotic

component and one biotic component of the ecosystem that gets affected by its

spread in the water body.

6. Name and explain any four lymphoid organs present in human.

7. How are Cucurbita plants different from papaya plants with reference to the flowers

they bear?

8. Explain the process of replication of a retrovirus, after it gains entry into the human

body.

9. Describe the development of endosperm after double fertilization in an angiosperm.

Why does endosperm development precede that of zygote?

10. Draw a labeled diagram of the sectional view of microsporangium of an angiosperm.

11. State the function of filiform apparatus found in mature embryo sac of an

angiosperm.

12. What id pollen- pistil interaction and how is it mediated?

13. Explain three advantages the seeds offer to angiosperm.

14. What are biofertilisers? Describe their role in agriculture. Why are they preferred to

chemical fertilizers?

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15. Explain double fertilization and trace the post-fertilisation events in sequential order

leading to seed formation in a typical dicotyledonous plant.

16. Why an apple is called as false fruit and a banana a parthenocarpic fruit? Explain.

17. Name the stage of human embryo at which it gets implanted. Explain the process of

implantation.

18. Explain the development of a secondary oocyte (ovum) in a human female from the

embryonic stage upto ovulation. Name the hormone involved in this process.

19. Explain the hormonal control of spermatogenesis in human.

20. Differentiate between the major structural changes in the human ovary during the

follicular and luteal phase of the menstrual cycle.

21. What is amniocentesis? How is it misused?

22. How do copper and hormone releasing IUDs act as contraceptives?

23. Why did T. H. Morgan select Drosophilia melanogaster to study sex-linked genes for

his lab experiment?

24. When do a genesist need to carry out a test cross? How is it carried out?

25. Explain the genetic basis of blood grouping in human population.

26. State and explain the law of dominance proposed by Mendel.

27. With the help of one example, explain the phenomenon of codominance and

multiple allelism in human population.

28. Why is the possibility of a human female suffering from haemophilia rare? Explain.

29. Write the life cycle of malarial parasite in the human body when bitten by an infected

female Anopheles.

30. How can crop varieties be made disease-resistant to overcome food crisis in India?

Explain. Name one disease resistant variety in India of:

(a) Wheat to leaf and stripe rust.

(b) Brassica to white rust.

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PHYSICAL EDUCATION

1. Fitness Tests Administration for all items.

2. Procedure for Asanas, Benefits and Contraindications for any two Asanas for each

lifestyle disease.

3. Procedure for administering senior citizen Fitness Test for 5 elderly family members.

4. Any one game of your choice out of the list below. Labelled diagram of field and

Equipment (Rules, Terminologies and Skills)-Print out.

(Basketball / Football / Kabaddi / Kho-Kho / Volleyball / Handball / Hockey / Cricket /

Bocce / Unified Basketball for CWSN (Children with Special Needs – Divyang).

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INFORMATICS PRACTICES

SECTION: A

Completion of Practical file

Completion of Project on given topic

SECTION: B

Answer the following questions:

I. (a) What is event driven programming?

(b) Name the method to set the value of jTextField.

(c) What is the difference between '=' and '==' operator?

(d) Give the name of the ternary operator.

(e) Write Java code that takes value for side of a square in jTextField1 and calculate

area of it to be displayed in jTextField2

(f) A worker_Id consisting of 4 digits is stored in a string variable StrWrkId. Now Mr.

Jai Wants to store this Id in integer type of variable IntwrkId. Write a Java statement

to do this

(g)Define a variable. How can you declare a variable?

II. (a)What is the effect of absence of break in switch statement?

(b)What is exit control loop?

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(c) Use an if statement to compare the value of an integer called sum against the

value 65 and if it is less, print the text string "sorry, try again"

(d) Rewrite the following program code using a switch statement.

If(code==1)

Month = 'January';

Else if(code==2)

Month = 'February';

Else if (code==3)

Month='March';

Else if(code==4)

Month='April';

Else

Month='no match';

(e) The following code has some error(s).Rewrite the correct code underlining all the

corrections made.

Int k=2;sum=0;

Sum =k;

K+=3;

While(k<=20)

jTextField1(Integer.toString(sum));

(f)What will be the values of variables 'm' and 'n' after the execution of the following

code?

Int m,n=0;

For(m=1;m<=4;m++)

n+=m;

n--;

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(g) Ms. Neelam works as a programmer in “Kidz Entertainment Zone”. She has

designed a Registration Page to calculate the total fee of summer camp depending upon

the number of activities selected by the user considering age eligibility as well. A screenshot

of the same is shown below

Help her in writing the code to do the following:

i. After entering the age in the specified text field, when „Chk Eligibility‟button is

clicked, a dialogue box should be displayed with a message “Welcome” if age is in

between 3-13 years else the program should be terminated after displaying the

message “Sorry! You are either underage or overage!!”

ii. After selecting the desirable activities, total fee should be displayed in the specified

text field on the click of “Proceed” button at the rate of Rs. 1000 per activity.

iii. A discount of 20% is applicable if more than one activity is chosen by the user.

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iv. After clicking on the “Net Fee” button, Net Fee should be calculated and displayed in

the respective text field as per the given formula:

NetFee = Fee – Discount

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COMPUTER SCIENCE

SECTION A

Completion of Practical file

Completion of Project on given topic

SECTION B

Answer the following questions:

1(a) What do you mean by data encapsulation? How is it implemented?

1(b) Name the header files to which the following belong:

(i) isalnum() (ii) abs()

1(c) Rewrite the corrected code for the following program. Underline each correction

(if any):

#include<iostream.h>

structure Swimmingclub

int mem number;

char memname[20];

char memtype[]="LIG";

;

void main()

Swimmingclub per1,per2;

cin<<"Member Number:";

cin>>memnumber.per1;

cout<<"Member Name:";

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cin>>per1.membername;

per1.memtype="HIG";

per2=per1;

cin<<"Member Number:"<<per2.memnumber;

cin<<"Member Name"<<per2.memname;

cin<<"Member Number:"<<per2.memtype;

1(d) What will be the output of the following program:

#include<iostream.h>

#include<ctype.h>

#include<conio.h>

#include<string.h>

void ChangeString(char Text[], int &Counter)

char *Ptr=Text;

int Length=strlen(Text);

for(;Counter<Length-2;Counter+=2,Ptr++)

*(Ptr+Counter)=toupper(*(Ptr+Counter));

void main()

clrscr();

int Position=0;

char Messages[]="Pointer Fun";

ChangeString(Message,Position);

cout<<Message<<'@"<<Position;

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1(e) Find the output of the following program:

#include<iostream.h>

#include<ctype.h>

#include<string.h>

void Convert(char Str[], int Len)

for(int Count=0; Count<Len;Count++)

if(isupper(Str[count]))

Str[Count]=tolower(Str[Count]);

else if(islower(Str[Count]))

Str[Count]=toupper(Str[Count]);

else if(isdigit(Str[Count]))

Str[Count]=Str[Count]+1;

else Str[Count]='*';

void main()

Char Text[]="CBSE Exam 2005";

int Size=strlen(Text);

Convert(Text,Size);

for(int C=0,R=size-1;C<=Size/2;C++,R--)

char Temp=Text[C];

Text[C]=Text[R];

Text[R]=Temp;

1(f) What is the difference between call by value and call by reference? Give example. ?

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2(a) What is the difference between private and protected data members of a class?

2(b) Answer the questions (i) and (ii) after going through the following class:

class Exam

int year;

public:

Exam(it y) year=y; //Constructor 1

Exam(Exam &t) //Constructor 1

;

(i) Create an object, such that it invokes Constructor 1.

(ii) Write complete definition for constructor 2.

2(c) Define a class STOCK in C++ with the following description:

Private members

ICode of type integer (Item Code)

Item of type string (Item Name)

Price of type float (Price of each item)

Qty of type integer (Quantity in stock)

Discount of type float (Discount percentage on the item)

A member function FindDisc() to calculate discount percentage as per the

following rule:

If Qty <=50 Discount is 0

If50<Qty<=100 Discount is 5

IfQty>100 Discount is 10

Public members

A function Buy() allow user to enter values for ICode, Item, Price, Qty and call

function FindDisc() to calculate Discount.

A function Show All() to allow user to view the content of all the data

members.

2(d) Answer the question (i) to (iv) based on the following code:

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class Trainer

char TNo[5], TName[20], Specialisation[10];

int Days;

protected:

float Remuneration;

void AssignRem(float);

public:

Trainer();

void TEntery();

void TDisplay();

;

class Learner

char regno[10], LName[20],Prpgram[10];

protected:

int Attendeance, Grade;

public:

Learner();

void LEntery();

void LDisplay();

;

class Institute:public Learner, public Trainer

char ICode[10],IName[20];

public:

Institute();

void IEntry();

void IDisplay();

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;

(i) Which type of Inheritance is depicted by the above example?

(ii) Identify the member function(s) that cannot be called directly from the objects of

class Institute from the following:

TEntry()

LDisplay()

IEntry()

(iii) Write name of all the member(s) accessible from member functions of class

Institute.

(iv) If class Institute was derived privately from class Learner and privately from class

Trainer, then, name the member function(s) that could be accessed through Objects

of class Institute.

3(a) void main()

char ch='A';

fstream fileout("data.dat",ios::out);

fileout<<ch;

int p=fileout.tellg();

cout<<p

What is the output if the file content before the execution of the program is the

string “ABC”

(Note that “ “ are not part of the file).

3(b) Assuming that a text file named TEXT.TXT already contains some text written into it,

write a function named vowelwords(), that reads the file TEXT1.TXT and creates a new file

named TEXT2.TXT, which shall contains only those words from the file TEXT1.TXT which

don’t start with an uppercase vowel(i.e., with ‘A’, ‘E’, ‘I’, ‘O’, ‘U’). For example, if the file

TEXT1.TXT contains

Carry Umbrella And Overcoat When it Rains

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then the file TEXT.2TXT shall contain Carry When it Rains

3(c) Assuming the class Vehicle as follows:

class vehicle

char vehicletype[10];

int no_of_wheels;

public:

void getdetails()

gets(vehicletype);

cin>>no_of_wheels;

void showdetails()

cout<<"Vehicle Type"<<vehicletype;

cout<<"Number of wheels="<<no_of_wheels;

;

Write a function shoefile() to read all the records present in an already existing binary

file SPEED.DAT and display them on the screen, also count the number of records present

in the file.

3(d) Create a function sroot () that returns the square root of its argument. Overload sroot

in three ways: have it returned the square root of an integer, a long integer and a double.

3(e) Differentiate between Public and Protected visibilities in context of Object Oriented

Programming giving suitable examples for each.

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MATHEMATICS

Complete the following Sums:

Relations and Functions

1. Let f: RR be defined as f(x) = 10x + 7. Find the function g: R R such that gof = fog

= IR

2. Let f: W W be defined as f(n) = n – 1, if n is odd and f(n) = n + 1, if n is even. Show

that f is invertible. Find the inverse of f. Here, W is the set of all whole numbers.

3. Show that the function f:R x R: -1 < x < 1 defined by f(x) = , x R is one-one

and onto function.

4. Show that the function f : R R given by f(x) = x3 is injective.

5. Give an example of two functions f: NN and g: N N such that gof is onto but f is

not onto.

6. Given a non-empty set X. Consider P(X), which is the set of all subset of X. Defined

the relation R in P(x) as follows: For subsets A and B in P(X), ARB if and only if A B. Is

R an equivalence relation on P(X)? Justify your answer.

7. Find the number of all onto functions from the set 1,2,3...n to itself.

8. Let S = a,b,c and T = 1,2,3. Find F-1 of the following functions F from S to T, if it

exists.

i) F = (a,3), (b,2), (c,1) ii) F = (a,2), (b,1),(c,1)

9. Let A = -1, 0 , 1, 2, B = -4, -2, 0 ,2 and f, g : A B be the function defined by f(x) =

x2 – x, x A, and g(x) = 2 -1, x A. Are f and g equal? Justify your answer.

10. Functions f, g : R R are defined respectively, by f(x) = x2 +3x + 1, g(x) = 2x – 3, find

i) Fog ii) gof iii) fof iv) gog

Inverse Trigonometric Functions

Prove the following Functions

1. cos -1 + cos -1 = cos -1

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2. sin -1 + sin -1 = tan -1

3. cos -1 + sin -1 = sin -1

4. tan -1 = sin -1 + cos -1

5. tan -1 + tan -1 + tan -1 + tan -1 =

6. cot -1 = , x

7. tan -1 = - cos -1x

8. - sin -1 = sin -1

9. tan -1 = = tan -1x, (x>0)

10. Find the value of tan -1 + cos -1

Continuity and Differentiability

Differentiate given problems w.r.t. x

1. , -2 < x < 2.

2.

3. x +xa + ax + aa , for some fixed a > 0 and x > 0.

4. + , for x>3.

5. Find , if y = sin -1x + sin -1 , -1 x 1.

6. If ( x – a)2+ (y –b)2 = c2 , for some c > 0, prove that is a constant independent

of a and b.

7. Using mathematical induction prove that = n x n-1 for all positive integers n.

8. Does there exist a function which is continuous everywhere but not differentiable at

exactly two points ? justify your answer.

9. If x = a ( cost + t sint) and y = a ( sin t – t cos t), find . mention the domain in which

it is valid.

10.

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APPLICATION OF DERIVATIVES

1. The two equal sides of an isosceles triangle with fixed base b are decreasing at the

rate of 3 cm/s. How fast is the area decreasing when the two equal sides are equal to

the base?

2. Find the equation of the normal to the curve y2 = 4x at the point (1,2).

3. Show that the normal at any point to the curve x = a cos + a sin , y = a sin - a

cos is at a constant distance from the origin.

4. Find the maximum area of an isosceles triangle inscribed in the ellipse + = 1, with

its vertex at one end of the major axis.

5. A tank with rectangular base and rectangular sides, open at the top is to be

constructed so that its depth is 2 m and volume is 8 m3. If building of tank costs Rs.

70 per sq metre for the base and Rs. 45 per sq metre for sides. What is the cost of

least expensive tank?

6. Fin the points at which the function f given by f(x) = (x -2)4(x+1)3 has

a) Local maxima b) local minima iii) point of inflexion

7. Find the absolute maximum and minimum values of the function f given by f(x) =

cos2x + sin x, x [0, ].

8. Show that the altitude of the right circular cone of maximum volume that can be

inscribed in a sphere of radius r is .

9. A window is in the form of a rectangle surmounted by a semi-circle opening. The

perimeter of the window is 10 m. Find the dimension of the window to admit

maximum light through the whole opening.

10. Show that the function given by f(x) = has maximum at x = e.

VECTOR ALGEBRA

1. Find a vector of magnitude 5 units and parallel to the resultant of the vectors a = 2 +

2 - and b = - 2 +

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2. Show that the points A(1,-2, -8), B (5, 0, -2) and C (11, 3, 7) are collinear and find the

ratio in which B divides AC.

3. The two adjacent sides of a parallelogram are 2 - 4 + 5 and - 2 - 3 . Find the unit

vector parallel to its diagonal. Also, find its area.

4. If a, b, c are mutually perpendicular vectors of equal magnitudes, show that the

vector (a + b +c) is equally inclined to a, b and c.

5. Prove that (a+b) . (a + b)= |a|2 + |b|2, if and only if a, b are perpendicular, given a 0,

b 0.

6. The scalar product of the vector + + with a unit vector along the sum of vectors 2

+ 4 -5 and + 2 +3 is equal to one. Find the value of λ

7. Let a = + 4 +2 , b =3 - 2 +7 and c =2 - +4 . Find a vector d which is

perpendicular to both a and b and c . d = 15.

8. Find the position vector of point R which divides the line joining two points P(2a + b)

and Q(a - 3b) externally in the ratio 1: 2. Also, show that P is the middle point of the

line segment RQ.

9. If a = b + c, then is it true that |a|= |b| + |c| ? justify your answer.

10. A girl walks 4 km towards west then, she walks 3 km in a direction 30 east of north

and stops. Determine the girl’s displacement from her initial point of departure.

ACTIVITIES

Complete the following Activities:

1. Activity 4

2. Activity 9

3. Activity 11

4. Activity 14

Note: Study all the Exemplar and Exercise sums of all the chapters that are covered.

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Chemistry

GENERAL INSTRUCTIONS:

A. Students are required to do this assignment in their class notebook.

B. All questions are compulsory.

C. Students are required to make one project on any topic from the prescribed

Syllabus mentioned in the practical book.

D. Learn the Scheme for inorganic salt analysis by heart.

SOLUTIONS

1. Vapour pressure of pure water at 298 K is 23.8 mm Hg. 50 g of urea (NH2CONH2) is

dissolved in 850 g of water. Calculate the vapour pressure of water for this solution

and its relative lowering.

2. Boiling point of water at 750 mm Hg is 99.63°C. How much sucrose is to be added to

500 g of water such that it boils at 100°C.

3. Calculate the mass of ascorbic acid (Vitamin C, C6H8O6) to be dissolved in 75 g of

acetic acid to lower its melting point by 1.5°C. Kf = 3.9 K kg mol-1.

4. 19.5 g of CH2FCOOH is dissolved in 500 g of water. The depression in the freezing

point of water observed is 1.00 C. Calculate the van’t Hoff factor and dissociation

constant of fluoroacetic acid.

5. Calculate the mass of a non-volatile solute (molar mass 40 g mol–1) which should be

dissolved in 114 g octane to reduce its vapour pressure to 80%.

6. A solution containing 30 g of non-volatile solute exactly in 90 g of water has a vapour

pressure of 2.8 kPa at 298 K. Further, 18 g of water is then added to the solution and

the new vapour pressure becomes 2.9 kPa at 298 K. Calculate: (i) molar mass of the

solute (ii) vapour pressure of water at 298 K.

7. A 5% solution (by mass) of cane sugar in water has freezing point of 271K. Calculate

the freezing point of 5% glucose in water if freezing point of pure water is 273.15 K.

8. Two elements A and B form compounds having formula AB2 and AB4. When

dissolved in 20 g of benzene (C6H6), 1 g of AB2 lowers the freezing point by 2.3 K

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whereas 1.0 g of AB4 lowers it by 1.3 K. The molar depression constant for benzene is

5.1 K kg mol–1. Calculate atomic masses of A and B.

9. Calculate the osmotic pressure in pascals exerted by a solution prepared by

dissolving 1.0 g of polymer of molar mass 185,000 in 450 mL of water at 37°C.

10. Vapour pressure of water at 293 K is 17.535 mm Hg. Calculate the vapour pressure of

water at 293 K when 25 g of glucose is dissolved in 450 g of water.

11. Henry’s law constant for the molality of methane in benzene at 298 K is 4.27 × 105

mm Hg. Calculate the solubility of methane in benzene at 298 K under 760 mm Hg.

12. 100 g of liquid A (molar mass 140 g mol–1) was dissolved in 1000 g of liquid B(molar

mass 180 g mol–1). The vapour pressure of pure liquid B was found to be 500 torr.

Calculate the vapour pressure of pure liquid A and its vapour pressure in the solution

if the total vapour pressure of the solution is 475 Torr.

ELECTRO CHEMISTRY

13. Calculate the emf of the cell in which the following reaction takes place

Ni(s) + 2Ag+ (0.002 M) → Ni2+ (0.160 M) + 2Ag(s)

Given that (cell) EV = 1.05 V

14. A solution of Ni(NO3)2 is electrolysed between platinum electrodes using a current of

5 amperes for 20 minutes. What mass of Ni is deposited at the cathode?

16. Predict the products of electrolysis in each of the following:

(i) An aqueous solution of AgNO3 with silver electrodes.

(ii) An aqueous solution of AgNO3with platinum electrodes.

(iii) A dilute solution of H2SO4with platinum electrodes.

(iv) An aqueous solution of CuCl2 with platinum electrodes.

17. The conductivity of 0.20 M solution of KCl at 298 K is 0.0248 S cm–1. Calculate its

molar conductivity

18. Using the standard electrode potentials given in Table 3.1, Predict if the reaction

between the following is feasible:

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(i) Fe3+(aq) and I–(aq)

(ii) Ag+ (aq) and Cu(s)

(iii) Fe3+ (aq) and Br– (aq)

(iv) Ag(s) and Fe 3+ (aq)

(v) Br2+ (aq) and Fe2+ (aq).

19. Write the Nernst equation and emf of the following cells at 298 K:

(i) Mg(s)|Mg2+(0.001M)||Cu2+(0.0001 M)|Cu(s)

(ii) Fe(s)|Fe2+(0.001M)||H+(1M)|H2(g)(1bar)| Pt(s)

(iii) Sn(s)|Sn2+(0.050 M)||H+(0.020 M)|H2(g) (1 bar)|Pt(s)

(iv) Pt(s)|Br2(l)|Br–(0.010 M)||H+(0.030 M)| H2(g) (1 bar)|Pt(s).

20. Given the standard electrode potentials, K+/K = –2.93V, Ag+/Ag = 0.80V, Hg2+/Hg =

0.79V Mg2+/Mg = –2.37 V, Cr3+/Cr = – 0.74V Arrange these metals in their increasing

order of reducing power.

CHEMICAL KINETICS

21. In a reaction, 2A → Products, the concentration of A decreases from 0.5 mol L–1 to

0.4 mol L–1 in 10 minutes. Calculate the rate during this interval?

22. A first order reaction has a rate constant 1.15 × 10-3 s-1. How long will 5 g of this

reactant take to reduce to 3 g?

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24.

25. The half-life for radioactive decay of 14C is 5730 years. An archaeological artifact

containing wood had only 80% of the 14C found in a living tree. Estimate the age of

the sample.

26. A first order reaction takes 40 min for 30% decomposition. Calculate t1/2.

25

27. The rate constant for the decomposition of hydrocarbons is 2.418 × 10–5s–1 at 546 K.

If the energy of activation is 179.9 kJ/mol, what will be the value of pre-exponential

factor.

28. Consider a certain reaction A → Products with k = 2.0 × 10–2s–1. Calculate the

concentration of A remaining after 100 s if the initial concentration of

A is 1.0 mol L–1.

29. Sucrose decomposes in acid solution into glucose and fructose according to the first

order rate law, with t1/2 = 3.00 hours. What fraction of sample of sucrose remains

after 8 hours ?

30. The decomposition of hydrocarbon follows the equation k = (4.5 × 1011s–1) e-

28000K/T Calculate Ea.

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PHYSICS

Electrostatics and Current Electricity

1. A capacitor of 400pF is charged by a 100V battery. The battery is then disconnected

and the charged capacitor is connected to another uncharged capacitor of 100 pF.

Calculate the difference between the final energy stored in the combined system

and the initial energy stored in the single capacitor.(

2. Net capacitance of three identical capacitors in series is 1 μF. What will be their net

capacitance if connected in parallel? Find the ratio of the energy stored in the two

configurations, if they are both connected to the same source. (9μF , 1:9)

3. A parallel plate capacitor is to be designed with a voltage rating of 1kV using a

material of dielectric constant 3 and dielectric strength 107 Vm-1. For safety we

would like the field never to exceed, say 10% of the dielectric strength. What

minimum area of the plate is required to have a capacitance of 50pF?

4. A conductor of length ‘l’ is connected to a dc source of potential ‘V’. If the length of

the conductor is doubled by gradually stretching it, keeping ‘V’ constant, how will (i)

– 0.4 × 10-6

J)

26

drift speed of electrons and (ii) resistance of the conductor be affected? Justify your

answer.

5. What is the ratio of initial and final resistance, when a metallic wire of length l

is stretched to double its length, assuming no change in density on

stretching?

6. Two wires of equal length, one of copper and the other of manganin have the

same resistance. Which wire is thicker?

7. When electrons drift in a metal from lower to higher potential, does it mean that

all the free electrons of the metal are moving in the same direction?

8. A wire of resistivity ρ is stretched to double its original length. What is its

new resistivity?

9. Two conducting wires X and Y of the same diameter but different materials are

joined in series across a battery. If the number density of electrons in X is twice that

in Y, Find the ratio of drift velocity of electron in the two wires.

10. A cylindrical metallic wire is stretched to increase its length by 10%. Calculate

the percentage increase in resistance.

11. A conductor of length l is connected to a dc source of potential V. If the length of the

conductor is tripled by gradually stretching it, keeping V constant, how will (i) drift

speed of the electrons and (ii) resistance of the conductor be affected? Justify your

answer.

Assignment 6

2. The plot of the variation of potential difference across a combination of three

identical cells in series, versus current is as shown below. What is the emf of each

cell? (2V)

27

3. A potentiometer wire of length 1 m is connected to a driver cell of emf 3 V as shown

in the figure. When a cell of 1.5 V emf is used in the secondary circuit, the balance

point is found to be 60 cm. On replacing this cell and using a cell of unknown emf,

the balance point shifts to 80 cm.

Calculate unknown emf of the cell. (2 0 V) Explain with reason, whether the

circuit works, if the driver cell is replaced with a cell of emf 1 V. Does the high

resistance R, used in the secondary circuit affect the balance point? Justify our

answer.

4. A cell of emf ‘E’ and internal resistance ‘r’ is connected across a variable resistor

‘R’. Plot a graph showing the variation of terminal potential ‘V’ with resistance R.

Predict from the graph the condition under which ‘V’ becomes equal to ‘E‘.

5. The figure shows experimental set up of a meter

bridge. When the two unknown resistances X and Y

are inserted, the null point D is obtained 40 cm from

the end A. When a resistance of 10 Ω is connected in

series with X, the null point shifts by 10 cm. Find the

position of the null point when the 10 Ω resistance is

instead connected in series with resistance ‘Y’.

Determine the values of the resistances X and Y.

(33.33 cm, X = 20Ω, Y = 30Ω)

6. A wire of resistance 8 R is bent in the form of a circle. What is the effective

resistance between the ends of a diameter AB? (2R)

28

7. In a meter bridge, the null point is found at a distance of 40 cm from A. If a

resistance of 12 Ω is connected in parallel with S, the null point occurs at 50.0 cm

from A. Determine the values of R and S. (R= 4Ω, S = 6Ω)

7. A resistance R is connected across a cell of emf e and internal resistance r. A

potentiometer now measures the potential difference between the terminals of the

cell as V. Write the expression for ‘r’ in terms of e, V and R.

8. In the circuit shown, R1 = 4 Ω, R2 = R3 = 15 Ω, R4 = 30 Ω and E = 10 V. Calculate the

equivalent resistance of the circuit and the current in each resistor. (I1 = 1A, I2 = I3 =

0.4A and I4 = 0.2A)

9. A cell of emf E and internal resistance r is connected to two external resistances R1

and R2 and a perfect ammeter. The current in the circuit is measured in four

different situations:

(i) without any external resistance in the

circuit.

(ii) with resistance R1 only

(iii) with R1 and R2 in series combination

(iv) with R1 and R2 in parallel combination.

The currents measured in the four cases are 0.42 A, 1.05 A, 1.4 A and 4.2 A, but not

necessarily in that order. Identify the currents corresponding to the four cases

mentioned above.

29

10. In the figure a long uniform potentiometer wire AB is having a constant potential

gradient along its length. The null points for the two primary cells of emfs ε1and ε2

connected in the manner shown are obtained at a distance of 120 cm and 300 cm

from the end A. Find (i) ε1 / ε2 and (ii) position of null point for the cell ε1. How is the

sensitivity of a potentiometer increased? (ε1 / ε2 =7/3, ε2 = 210 cm)

11. Using Kirchoff’s rules determine the value of unknown resistance R in the circuit so

that no current flows through 4 Ω resistance. Also find the potential difference

between A and D. (R 2 VAD = 3V)

12. Two students ‘X’ and ‘Y’ perform an experiment on

potentiometer separately using the circuit given:

Keeping other parameters unchanged, how will the

position of the null point be affected it

(i) ‘X’ increases the value of resistance R in the

set-up by keeping the key K1 closed and the key

K2 open?

(ii) ‘Y’ decreases the value of resistance S in the

set-up, while the key K2 remain open and the key

K1 closed?

Justify.

13. A resistance R 2 is connected to one of the gaps in a

metre bridge, which uses a wire of length 1 m. An

unknown resistance X 2 is connected in the other

gap as shown in the figure. The balance point is noticed

at ‘ l’ from the positive end of the battery.

30

14. On interchanging R and X, it is found that the

balance point further shifts by 20 cm (away from end A).

Neglecting the end correction, calculate the value of

unknown resistance X used. (X= 3Ω)

HAPPY HOLIDAYS

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GENERAL STUDIES

The following projects has to be done by the respective group of students as group

activity. All the content of the topic has to be covered in the project.Hand written

document and respective presentation (Power point presentation, model, role play, skit,

etc.,) has to be submitted during first week of September.

GROUP 1: SCIENCE AND SOCIETY

Content

1. The Nature of Science

Different aspects of Science, viz. the content, process and attitude

The language of Science- facts, hypothesis, theories and laws

2. Science as a social enterprise

The manner in which modern Science and technology shape modern culture,

values, and institutions on one hand and how modern values shape Science and

technology on the other

The progress of Science- major landmarks in the history of Science in India

3. The Scientific spirit

Scientific attitude

Dispelling superstitions and myths

The students may:

1. Do a small project, where they identify a problem, frame hypothesis, gather data and

analyze it to test the hypothesis.

2. Organize a debate for the whole class on ‘Science - a boon or bane’.

31

3. Identify given set of statements as facts, laws and hypothesis.

GROUP 2: CONTEMPORARY PROBLEM OF INDIAN SOCIETY

1. Poverty

Meaning, genesis and broad measures to alleviate it

Nature of poverty in rural and urban India

2. Illiteracy

Causes and consequences

Measures to eradicate illiteracy

3. Unemployment

Nature and extent of unemployment

Ameliorative measures to reduce unemployment - Vocational education, skill

based education

4. Social Inequalities

Kinds

Implications

The way forward

5. Population and health

declining sex ratio

infant mortality

malnutrition

obesity and other lifestyle diseases

The students may:

1. Make group presentations (collage, charts, posters) on the contemporary problems of

Indian society by using only newspaper clippings as a resource.

2. Conduct a small survey on status of literacy/employment/income in their locality.

3. Contribute towards solving social problems such as illiteracy. Students may volunteer to

teach one illiterate person in their locality.

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GROUP 3: CULTURAL HERITAGE OF INDIA

Content

1. The historical framework of India’s heritage and culture

2. Evolution of Indian culture

Historical background- from the Indus Valley civilization to the British period and

Indian renaissance

Shaping of Indian ethos and syncretism

3. The cultural heritage of India

Performing arts- dance, music, theatre etc.

Language and literature

Crafts

Paintings

Architecture

Cuisines

Textiles

The students may:

1. Read and discuss excerpts from various world literature with universal messages, writings

of poets (such as Kabir), philosophers, prophets, historians of the renaissance period such

as Raja Ram Mohan Roy, Vivekananda, etc.

2. Effectively use paintings, short films and other material developed by the Centre for

Cultural Resources and Training (CCRT) to appreciate the arts, crafts and architecture of

India.

3. Develop resource files on Sufi saints of Kashmir/Delhi/Rajasthan etc. Poets/saints of the

Bhakti period. Mughal influence on Indian architecture. Relevance of the teachings of Kabir/

Thiruvalluvar in today’s Indian society.

4. Practice meditation, ‘pranayam’ and ‘yogasana’ for health benefits and better

understanding of Indian culture.

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GROUP 4: CONSTITUTIONAL VALUE

Content

1. Preamble to the Indian Constitution (understanding the spirit of the Constitution):

Justice: Social, economic and political

Liberty of thought, expression, belief, faith and worship

Equality of status and of opportunity

Fraternity, the dignity of individual and the unity and integrity of the Nation

Secularism

2. Key features of the Constitution of India

Fundamental Rights, Directive Principles of State Policy and Fundamental Duties

Citizenship

Organs of Government

Federalism

3. Some legal provisions (relevant to children)

The students may:

1. Work in groups of 5-7 and develop a code of conduct which may relate to one of the

Fundamental Duties.

2. Work in groups of 5-7 and come to consensus on an area of interest after discussion

among themselves. They may then display their ideas/views on display boards in the

form of comic strips, pictures, cartoons, slogans, etc. This action well help cover the

themes of the unit and showcase the students’ concerns.

3. Prepare biographies of the makers of the Constitution.

4. Read excerpts from the Constitution of India. For this purpose, the teacher may

arrange a copy for the students.

5. Read the Preamble to the Constitution of India and highlight the values reflected in it.

They may then present a play to showcase these values.

34

GROUP 5: HUMAN RIGHTS

1. Human rights:

Historical perspective

The philosophical foundations of human rights

The United Nation’s declaration of human rights

Civil and political rights

Economic, social and cultural rights

Human rights of vulnerable groups

Human rights: Violation and remedies

Gender equality

The students may:

1. Read articles related to human rights, for example, United Nation’s Universal Declaration

of Human Rights and discuss them in class.

2. Observe their surroundings for any human rights violation. They may share the case with

the class and also suggest ways to deal with such violation.

3. Form an anti-bullying/anti-ragging group in school to ensure that no violation of

students’ rights take place.

4. Read the literature of different cultures and identify the common message of humanity

as envisaged through the provisions of human rights.

5. Prepare short investigatory projects based on current events as reported in the press and

identify:

Who is the victim?

Who has violated his/her human rights?

Which right has been violated?

What is the abuse committed?

How was the victim protected?

The project may be shared with the class.

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