first terminal examination - 2076 zoology (group b) botany ...21. define molarity and mole fraction....

$: First Terminal Examination - 2076 Zoology (Group B) Botany ...21. Define molarity and mole fraction. 25cc of an alkali solution is mixed with 8cc of 0.75N acid solution and for complete$
First Terminal Examination - 2076 GRADE: XII (Science)

Subject: Biology Set: A Full Marks: 75

Time: 3:00hrs. Pass Marks: 30

Botany (Group A)

1. Very short questions, any seven s[7x1=7]

a) Define permanent tissue.

b) What is the function of Aerenchyma?

c) What are the elements of xylem?

d) Define sclerenchyma.

e) Define variation.

f) What is nucleotides?

g) Define homozygous.

h) What is incomplete dominance?

i) What are the types of RNA?

j) Define transcription.

2. Short questions, any five [5x3=15]

a) Describe the structure of phloem.

b) Describe collenchymatous tissues.

c) Explain Mendel’s monohybrid cross.

d) Describe co-dominance.

e) Describe the structure of DNA.

f) Prove that DNA is a hereditary materials.

g) Describe the tunica and corpus theory.

3. Describe semi-conservative mode of DNA replication. [8]

4. Describe the internal structure of a dicot root and differentiate it with

monocot root.

OR

Describe the secondary growth in dicot plant. [7.5]

Zoology (Group B)

1. Answer in very short. (Any seven) 1×7=7

a) Define tissues.

b) Why is squamous epithelium also called pavement epithelium?

c) Name the protein filament responsible for formation of light band in

skeletal muscle.

d) Differentiate between active absorption and passive absorption.

e) Which enzyme curdles milk?

f) What is chloride shift?

g) What is the full form of DOTS?

h) What is the function of uvula?

i) What is erythropoiesis?

j) What is lecithin?

2. Answer in brief. (Any five) 3×5=15

a) Write a note on areolar tissue.

b) Enlist the functions of human liver.

c) Write about the mechanism of breathing in man.

d) Describe the structure of a bone.

e) Draw a well-labelled diagram of L.S. of human tooth.

f) Write a note on artificial respiration in man.

g) Write a note on absorption of fats in human body.

3. Describe the alimentary canal in man.

OR 7.5 marks

Describe the physiology of respiration in man.

4. What do you mean by communicable diseases? Write a note on

typhoid. 8

----------- GOOD LUCK ------------


Subject: Biology Set: B Full Marks: 75


Botany (Group A)

1. Very short questions, any seven [7x1=7]

a) Define meristem.

b) What is the function of chlorenchyma?

c) What are the elements of phloem?

d) What are the types of sclerenchyma?

e) Define clone.

f) What is replication fork?

g) Define punnett square.

h) What is co-dominance?

i) What is the function of DNA ligase?

j) What is the function of sigma and Rho-factor during transcription?

2. Short questions, any five [5x3=15]

a) Describe the structure of xylem.

b) Describe different types of vascular bundles.

c) Explain Mendel’s dihybrid cross.

d) Describe incomplete dominance.

e) Describe the structure of tRNA.

f) Describe Griffith’s experiment.

g) Write the significance of variation.

3. What is genetic material? Describe the structure of DNA and write its

significance. [8]

4. Describe the internal structure of a dicot stem and differentiate it with

monocot stem.

OR

Describe the process of secondary growth in dicot stem. [7.5]

Zoology (Group B)

1. Answer in very short. (Any seven) 1×7=7

a) Who is the father of histology?

b) Why is transitional epithelium called urothelium?

c) Name the pigment that gives coloration to muscle fibres.

d) Differentiate between cartilage and ligament.

e) What is leucopoiesis?

f) What is Bohr effect?

g) What is the full form of BCG?

h) Write any two functions of larynx.

i) Where would you find keratinized epithelium?

j) What is pleura?

2. Answer in brief. (Any five) 3×5=15

a) Write a note on adipose tissue.

b) Write a note on human pancreas.

c) How is CO2 transported from tissues to lungs?

d) Describe the structure of a bone.

e) Draw a well-labelled diagram of human buccal cavity.

f) Write a note on striated muscle.

g) Write a note on digestion of proteins in human body.

3. Describe the alimentary canal in man.

OR 7.5

Describe the physiology of respiration in man.

4. What do you mean by communicable diseases? Write a note on

tuberculosis. 8

----------- GOOD LUCK ------------

1

First Terminal Examination - 2076 GRADE: XII

Subject: Chemistry Set: B Full Marks: 75


Group A

Attempt any fifteen questions. [15 x 2 = 30]

1. Identify the order of a reaction if the unit of its rate constant is sec-1.

2. What do you mean by acidity? The molecular weight and equivalent

weight of NaOH is same but not same in Ca(OH)2. Why?

3. Calculate the amount of NaOH required to prepare 250ml of 0.1N of its

solution.

4. Define PH and POH. Derive the relationship between them.

5. What do you mean by conjugate acid base pair? Explain with suitable

example.

6. Differentiate between rate and rate constant of a reaction.

7. State Huckel’s rule of aromaticity. Illustrate the rule taking an example.

8. Convert 1-bromopropane to 2-bromopropane.

9. Why do alcohols have higher boiling points than corresponding

haloalkane and hydrocarbon?

10. What is wurtz fittig reaction. Give an example.

11. How would you convert ethoxy ethane into methoxy ethane.

12. What are amines. Give one example of primary, secondary and tertiary

amine with their IUPAC names.

13. Give reason why aliphatic amine is more basic than Ammonia?

14. Covert chlorobenzene to aniline.

15. Write an example of each of the following (a) diazotization reaction (b)

carbylamines reaction.

2

16. Why is -NO2 group a meta directing towards electrophilic substitution

reaction.

17. Define esterification reaction with suitable examples.

Group B

Attempt any five questions. [5x5=25]

18. What is meant by Grignard’s reagent? How would you prepare primary,

secondary and tertiary alcohol from Grignard reagent? Illustrate with

specific reactions. (1 + 4)

19. Write the primary and secondary amine of the molecular formula C2H7N.

How would you separate these compounds by Hoffmann method of

separation? (2 + 3)

20. An alcohol (A) reacts with thionyl chloride to produce (B), which on

dehydrohalogenation yielded a compound (C). The compound (C) on

ozonolysis gave the mixture of ethanal and methanal. If the alcohol (A)

responses positive iodoform test, Identify (A), (B) and (C) with pertinent

reactions.

21. What is the relationship between normality and molarity. If 20 ml of 0.5N

NaOH is mixed with 30ml of 0.4N HCl. Is the resulting solution acidic or

basic? Calculate the normality with respect to the acidic or basic final

solution. (1.5+3.5)

22. What are the advantages of lewis concept? A solution is found to

contain 0.63gm of nitric acid per 100ml of the solution. What is the PH of

the solution if the acid is completely dissociated. (2+3)

23. The experimental data for the decomposition of N2O5 in gaseous phase

at 318K is as follows: 2N2O5 (g) → 4NO2 (g) + O2 (g)

Time (Sec) [N2O5] molL-1 Time (Sec) [N2O5] mol L-1

0 1.36x10-2

400 1.36x10-2 1600 0.78x10-2

800 1.14x10-2 2000 0.64x10-2

1200 0.95x10-2 2400 0.53x10-2

Calculate the

1) Rate law,

2) Rate constant,

3) Order of reaction and

4) Half life period of the reaction.

Group C

Attempt any two questions [2x10=20]

24. Describe the preparation of pure and dry aniline in the laboratory.

Starting from aniline how would you obtain

(a) O-nitro aniline

(b) Sulphanilic acid

(c) Benzanilide. (6+2+1+1)

25. a) Why selection of indicator is most important for acid base titration?

b) What do you mean by solubility product and its principle? The

solubility of AgCl in water at 298k is 1.43x10-3g/l. Calculate its

solubility in 0.5M KCl. (4+3+3)

26. Write short notes on (any two)

a) Factors affecting the rate of chemical reaction.

b) Fermentation of carbohydrates.

c) Reduction reactions of nitrobenzene in neutral medium

The End

1


Subject: Chemistry Set: A Full Marks: 75


Group A

Candidates are required to answer in their own words as far as practicable. The figures in the margin indicate full marks.

Attempt any fifteen questions. [15 x 2 = 30]

1. Identify the order of a reaction if the unit of its rate constant is Lit mol-1

sec-1.

2. What do you mean by basicity? Why is basicity of H2SO4 and H3PO4

same?

3. What volume of water is required to make 100ml of N/10(f=1.25) HCl

solution exactly decinormal?

4. What is the significance of ionic product of water?

5. State the Bronsted Lowery concept of acid and base. Show that water

acts both acid as well as base according to this concept.

6. Differentiate between order and molecularity of a reaction.

7. Why do aromatic compounds burn with sooty flame?

8. Convert 2-bromopropane to 1-bromopropane.

9. Alcohols are soluble in water but alkanes are not. Why?

10. What is wurtz reaction? Give an example.

11. How would you convert methoxy ethane into ethoxy ethane?

12. Write the possible isomeric amines of C3H9N and give their IUPAC

names.

13. Give reason why aniline is less basic than methylamine?

14. Convert Nitrobenzene to chlorobenzene.

15. What happens when (a) aniline is shaken well with bromine water? (b)

Aniline is coupled with benzene diazonium chloride?

16. What happens when nitrobenzene is reduced in acidic and neutral

medium?

17. How would you obtain ethanol from cane sugar? Write reactions only.

Group B

Attempt any five questions. [5x5=25]

18. Write the secondary and tertiary isomeric alcohols of molecular formula

C4H10O and show how you can separate these isomers using Victor

Meyer’s Method.

19. Compound ‘A’ is treated with nitrating mixture to give compound ‘B’,

which on reduction gives compound ‘C’. Compound ‘C’ on reacting with

the mixture of NaNO2 and HCl gives compound D. Compound D on

reacting with phenol at cold gives a dye ‘E’. If compound ‘A’ is obtained

by heating phenol with Zn dust, identify Compound A,B,C D and E with

the reaction involved.

20. Describe the laboratory preparation of Nitrobenzene. How is it purified?

21. Define molarity and mole fraction. 25cc of an alkali solution is mixed

with 8cc of 0.75N acid solution and for complete neutralization it further

requires 15cc of 0.8N acid solution. Find the strength of the given alkali.

(2+3)

22. What are limitations of lewis concept? Calculate the PH of the solution

obtained by mixing 100cc of solution of PH=3 with 400cc of solution of

PH=4. (2+3)

2

23. The following rate data were obtained at 300K for the reaction 2A+B →

C+D

Exp.no. [A] Mol L-1 [B] Mol L-1 Rate of formation of D, Mol L-1

Min-1

1. 0.1 0.1 5.0x10-3

2. 0.3 0.2 6.0x10-2

3. 0.3 0.4 2.4x10-1

4. 0.4 0.1 2.0x10-2

Calculate the (a) order of reaction with respect to A and B. (b) Rate

constant of the reaction. (c)The rate of formation of D, When [A] =

0.5mol L-1 and [B] = 0.2 mol L-1.

Group C

Attempt any two questions. [2x10=20]

24. Describe the preparation of pure and dry chloroform in the laboratory.

Give its action with (a) silver (b) aq. KOH (c) aniline in the presence of

aq. NaOH.

25. a) Write the chemical applications of common ion effect and

solubility product. (4)

b) Write the characteristics of primary standard substance. 100ml of

4.5x10-5 Na2S solution is mixed with 200ml of 1.3x10-3M AgNO3

solution. Is precipitation of Ag2S possible after mixing? (Ksp of

Ag2S = 1.6x10-19) (2+4)

26. Write short notes on (any two)

a) Collision theory of bimolecular reaction

b) Influence of catalyst and temperature on the rate of reaction.

c) Laboratory preparation of diethyl ether.

The End


Subject: Comp. English Set A Full Marks: 100


Candidates are required to give their answers in their own words as far as

practicable. The marks are given against each of the questions.

1. Read the following text and answer the questions given

below. 5x3=15

The modern age is an age of electricity. People are so used to electric

lights, radio, televisions, and telephones that it is hard to imagine what life

would be like without them. When there is a power failure, people grope

about in flickering candlelight. Cars hesitate in the streets because there

are no traffic lights to guide them, and food spoils in silent refrigerators.

Yet, people began to understand how electricity works only a little more

than two centuries ago. Nature has apparently been experimenting in this

field for millions of years. Scientists are discovering more and more that

the living world may hold many interesting secrets of electricity that could

benefit humanity.

All living cells send out tiny pulses of electricity. As the heart beats, it

sends out pulses of recorded electricity; they form an electrocardiogram,

which a doctor can study to determine how well the heart is working. The

brain, too, sends out brain waves of electricity, which can be recorded in

an electroencephalogram. The electric currents generated by most living

cells are extremely small-of-ten so small that sensitive instruments are

needed to record them. But in some animals, certain muscle cells have

become so specialized as electrical generators that they do not work as

muscle cells at all. When large numbers of these cells are linked together,

the effects can be astonishing.

The electric eel is an amazing storage battery. It can send a jolt of as

much as eight hundred volts of electricity through the water in which it

lives. An electric house current is only one hundred twenty volts. As many

as four fifths of all the cells in the electric eel’s body are specialized for

generating electricity, and the strength of the shock it can deliver

corresponds roughly to the length of its body.

Questions:

(a) What does the passage primarily deal with?

(b) According to the passage, how long is the history of electricity?

(c) Why does the author mention electric eels?

(d) How are biology and electricity related?

(e) Give a suitable title to the passage.

3. Answer ANY ONE of the following: 10

i. What is the contextual significance of the use of anecdotes in the

story? How do these anecdotes help us to understand Alyohin’s

character? Explain in detail. (About Love).

ii. According to Moti Nissani, what are the causes, consequences and

cures of overpopulation and deforestation?

4. Answer ANY FIVE of the following questions: [5x3 = 15]

i. What makes the poem ‘Grandmother’, a nostalgic poem.

ii. Explain, ‘Love is different in each situation’. (About Love)

iii. How does the speaker feel about old age in ‘The Lamentation of the

Old Pensioner’?

iv. How is death presented in the poem ‘Full Fathom Five Thy Father

Lies’?

v. What did the two writers learn about the life and activities of the

people of the Karnali region during their journey on foot? (Hurried Trip

to Avoid a Bad Star)

2. How would you describe a person who………… 5

Example: gives away lots of money ……..generous person

i. doesn’t boast……………

ii. only thinks about himself/herself……………….

iii. always sees the dark side of life…………………

iv. never buys the children a doll……………………

v. easily loses his/her temper………………….

3. Make a list of experiences and/ or achievements for the given person

in five sentences. 5

i. The new party leader, Andrew Fife, is a man of wide and varied

experience.

4. Rewrite the following sentences using ‘seem’. 5

i. You see someone climbing through a window.

ii. The manager listens to his staffs and takes their matter seriously.

iii. Nirnaya always sits on the first bench in the class.

iv. He has nicotine stains on his fingers.

v. Everybody wears masks in Kathmandu.

5. Rewrite the sentences combining together using non defining

relative clause. 5

i. Godfrey decided to be an actor. His parents had been in the theatres.

ii. She lives in New York. She likes living in New York.

iii. The dog was sitting facing the garden. The dog loved travelling in fast

cars.

iv. Mary noticed that he was wearing her ring. She has lost it for five

years before.

v. This was my father's oldest house. I was born in this house.

6. Look at the example, and write about the other topics in the same way.

5

Example:

mean people

The meanest person I ‘ve ever met was Jack Davies. He used to walk

everywhere rather than pay for the bus.

i. high marks in the exam

ii. frightening experiences

iii. funny film

iv. boring jobs

v. stupid mistakes

7. Rewrite the following sentences supplying the correct from of the

words given in the bracket. 5

[ embarrass, offend, annoy, irritate, disgust]

i. His comments were deeply ……….to a large numbers of single

mothers.

ii. It really…………..me when people forget to say thank you.

iii. I have never felt so……………in my life.

iv. I think it’s ………….that they’re closing the local hospital.

v. The way she puts on that accent really …………….me

8. Give arguments for and against the statement: “There is intelligent life on

other planets”. 10

9. Write a police description of a person who has been missing for a week. 5

10. Stating suitable qualifications and experience, write a letter of application

for the post of Primary Level Science Teacher. 10

11. Write some paragraphs on “The day I can never forget”. 5

***


Subject: Comp. English Set B Full Marks: 100


Candidates are required to give their answers in their own words as far as

practicable. The marks are given against each of the questions.

1. Read the following text and answer the questions given

below. 5x3=15

There were two widely divergent influences on the early development of

statistical methods. Statistics had a mother who was dedicated to keeping

orderly records of governmental units (state and statistics come from the

same Latin root. status) and a gentlemanly gambling father who relied on

mathematics to increase his skill at playing the odds in games of chance.

The influence of the mother on the offspring, statistics, is represented by

counting, measuring, describing, tabulating, ordering, and the taking of

censuses-all of which led to modern descriptive statistics. From the

influence of the father came modern inferential statistics, which is based

squarely on theories of probability.

Descriptive statistics involves tabulating, depicting, and describing

collections of data. These data may be either quantitative, such as

measures of height, intelligence, or grade level-159 variables that are

characterized by an underlying continuum-or the data may represent

qualitative variables, such as sex, college major, or personality type.

Large masses of data must generally undergo a process of

summarization or reduction before they are comprehensible. Descriptive

statistics is a tool for describing or summarizing or reducing to

comprehensible form the properties of an otherwise unwieldy mass of

data.

Inferential statistics is a formalized body of methods for solving another

class of problems that present great difficulties for the unaided human

mind. This general class of problems characteristically involves attempts

to make predictions using a sample of observations. For example a

school superintendent wishes to determine the proportion of children in a

large school system who come to school without breakfast have been

vaccinated for flu or whatever. Having a little knowledge of statistics, the

superintendent would know that it is unnecessary and inefficient to

question each child; the proportion for the entire district could be

estimated fairly accurately from a sample of as few as 100 children. Thus,

the purpose of inferential statistics is to predict or estimate characteristics

of a population from a knowledge of the characteristics of only a sample

of the population.

Questions:

i. What are the parental sources of statistics?

ii. Define descriptive statistics and how is it different from

inferential statistics?

iii. What is the general purpose of statistics?

iv. What are variables and how are they classified?

v. Give a suitable title for the passage.

2. Answer ANY ONE of the following: 10

i. Give your idea on ‘Youth and Age’. You may base your answer on the

poem ‘Lamentation of the Old Pensioner’.

ii. What are the two-long term problems, Moti Nissani discusses in his

essay and also write how do they affect our ecological system?

4. Answer ANY FIVE OF the following questions: [5 x 3 = 15]

i. Write two paragraphs describing the economic activities of Karnali

Zone people? (Hurried Trip to Avoid the Bad Star)

ii. Describe the importance of the images of shape, hands and voice in

the poem ‘Grandmother’ and also write how these images make the

poem appealing.

iii. Why does the speaker compare himself with a broken tree?

(Lamentation of the Old Pensioner)

iv. Who sang the song ‘Full Fathom Five Thy Father Lies’ to whom and

why?

v. How does the story ‘About Love’ deal with the issue of class

difference through love?

5. Write definitions for the following. 5

i. A vain person

ii. A credulous person

iii. A placid person

iv. A clumsy person

v. A skeptical person

6. Rewrite the following sentences using ‘Look as if + present perfect’.5

i. You see a man standing outside the gate.

ii. You see a man and a woman talking about their honeymoon trip.

iii. You see a man lying on the floor, laughing.

iv. You see some students discussing about the questions.

v. You see a woman bargaining in a shop.

7. Rewrite the following sentences using ‘(not) used to + ing’. 5

i. Street children beg money from tourists.

ii. Suman walks to the office.

iii. I don’t eat street foods.

iv. Ms. Sudha teaches school children.

v. Khalid sings hip-hop songs.

8. Write a police description of a person who has been involved in gold

smuggling. 5

9. Prepare a speech for or against the statement “A student should have

good knowledge of his national affairs.” 10

10. Stating suitable qualifications and experience, write a letter of application

for the post of Primary Level English Teacher. 10

9. Rewrite the sentences below, beginning with the words given in the

brackets. 5

i. Has anyone ever taken your photo? (Have you ever……)

ii. Someone is laughing at Sita. It’s making her angry. (If there is one

thing…………… )

iii. He is well built and his hands are rough. (He seems………)

iv. I am very much happy today. (This is the first time…………)

v. Look how fast he’s driving. I am really impressed. (I find……..)

10. Rewrite the sentences combining together using non-defining

relative clause. 5

i. Occasionally, Mother had us meet her. We seldom saw her in the house.

ii. The boy started a fire in the classroom. His parents both worked as

teachers at school.

iii. I live in a city. I study in the city.

iv. Mary noticed that he was wearing her ring. She has lost it for five years

before.

v. They live in a house. The roof of the house is full of holes.

11. Write five more sentences for the situation given below explaining what

things were like and what changes had taken place.

5

When I went back to the village where I had grown up, it was almost

unrecognizable.

12. Write some paragraphs about the most memorable day in your student life

at school”. 5


Subject: Mathematics SET- B Full Marks: 100


Group A [(5 x 3) x 2 = 30]

1. a. Eight members of a committee sit at a round table. In how many

ways can they seated if president and secretary choose to sit

together?

b. Find the feasible regions determined by the inequality 3𝑥 + 2𝑦 ≤ 18,

𝑥 + 𝑦 ≥ 6, 𝑥 ≥ 0.

c. Find the term independent of x in the expression of (𝑥 +1

3𝑥2)12

2. a. Show that: 2

1!+4

3!+6

5!+⋯ 𝑡𝑜 ∞ = 𝑒

b. If 𝑦 =𝑥

1!+𝑥2

2!+𝑥3

2!+⋯ 𝑡𝑜 ∞ then show that:

𝑥 = 𝑦 −𝑦2

2+𝑦3

3+𝑦4

4+⋯𝑡𝑜 ∞

c. Find the equation of the parabola with vertices at (1,2) and the focus

at (0,2).

3. a. Integrate: ∫√2𝑎𝑥 − 𝑥2 𝑑𝑥

b. ABCD is a parallelogram. where 𝐺 is the point of intersection of its

diagonals and if 𝑂 is any point, Show that 𝑂𝐴→ +

𝑂𝐵→ +

𝑂𝐶→ +

𝑂𝐷→ =

4𝑂𝐺→

c. If 3𝑖 + 𝑗 − and 𝛼𝑖 − 4𝑗 + 4 are collinear vectors, find the value of

𝛼.

4. a. Convert the decimal number 7510 to the binary number.

b. Find the area of a parallelogram whose diagonal are represents by

the vectors −3𝑖 − 2𝑗 + and 𝑖 + 2𝑗 + 3.

c. Find the derivative of 𝑥𝐶𝑜𝑠ℎ2𝑥

𝑎

5. a. Evaluate: lim𝑥→0

𝑒𝑥+𝑒−𝑥−2𝐶𝑜𝑠𝑥

𝑆𝑖𝑛2𝑥

b. Integrate: ∫𝑑𝑥

𝑒𝑥+𝑒−𝑥

c. Solve: 𝑑𝑥

𝑑𝑦=𝑒𝑥+1

𝑦

Group B [(5 x 2) x 4 = 40]

6. a. 5 men in a group if 12 are graduates. In how many committees of 6

members be made of that each committee may consist of 3

graduates?

b. Sum to infinity the series: 12

1!+22

2!+32

3!+⋯

7. a. Find the equation of parabola in standard form (whose vertex is at

(0, 0) and axis along X-axis.

b. Integrate: ∫1

1−2𝐶𝑜𝑠𝑥𝑑𝑥

8. a. Solve: 𝑥2𝑑𝑦

𝑑𝑥+ 𝑦2 = 𝑥𝑦

b. Solve: (𝑥 + 1)𝑑𝑦

𝑑𝑥+ 2𝑦 =

𝑒𝑥

𝑥+1

9. a. Integrate: ∫𝑑𝑥

(𝑥−1)2(𝑥−2)2

b. Prove that the vectors 5 + 6 + 7𝑐 , 7 − 8 + 9𝑐 and 3 + 20 +

5𝑐 are coplanar, where , , 𝑐 are any three vectors.

10. a. In how many ways can the letters of the word “MONDAY” be

arranged? How many of these arrangements da not begin with M?

How many begin with M and do not end with Y?

b. Find the co-ordinates of the focus, vertex, equation of directrix and

the length of latus rectum of the parabola 𝑦2 = 6𝑦 − 12𝑥 + 45

Group C [6 x 5 = 30]

11. What is the binomial coefficient on the expression of (𝑎 + 𝑥)𝑛. If

(1 + 𝑥)𝑛 = 𝐶𝑜 + 𝐶1𝑥 + 𝐶2𝑥2 +⋯+ 𝐶𝑛𝑥

𝑛, Prove that:

𝐶𝑜𝐶𝑛 + 𝐶1𝐶𝑛−1 +⋯+ 𝐶𝑛𝐶𝑜 =2𝑛!

𝑛!𝑛!

12. Prove by the vector method: 𝐶𝑜𝑠(𝐴 + 𝐵) = 𝐶𝑜𝑠𝐴𝐶𝑜𝑠𝐵 − 𝑆𝑖𝑛𝐴𝑆𝑖𝑛𝐵

13. State mean value theorem. Interpret it geometrically. Verify it for the

function 𝑓(𝑥) = (𝑥 − 1)(𝑥 − 2)(𝑥 − 3)𝑖𝑛 [1,4]

14. Form the first principle, the derivative of e𝐶𝑜𝑠𝑥

15. Determine the maximum and minimum values if the function 𝐹(𝑥, 𝑦) =

10𝑥 + 15𝑦 for the feasible region defined by 𝑥 + 2𝑦 ≤ 20, 𝑥 − 𝑦 ≤ 16,

𝑥, 𝑦 ≥ 0

THE END


Subject: Physics Set: A Full Marks: 75


Group A

1. Attempt any four questions. (4x2=8)

a. A wire is stretched to double its length. What will happen to its resistivity and resistance?

b. You are given ‘n’ wires, each of resistance R. What is the ratio of maximum to minimum resistance obtainable from these wires?

c. Two bulbs have the filament of the same length. If one is of 40 Watt and the other 60 Watt, which one has thicker filament.

d. Is terminal p.d. of a cell always greater than its emf?

e. Why do we prefer a potentiometer to measure emf of a cell rather than a voltmeter?

f. Can a charge particle move through a magnetic field without experiencing any force? Explain.


a. Gases are insulators at ordinary pressure and start conducting at low pressure. Why?

b. Compare the specific charge of an electron with that of a proton.

c. Explain why photoelectric effect cannot be observed with all wavelengths of light.

d. An electron and α-particle have the same kinetic energy. What is the ratio of de-Broglie wavelengths associated with them?

e. Distinguish between stimulated emission and spontaneous emission.

f. An electron is in the third excited state of a H-atom. How many different photon wavelengths are possible?

3. Attempt any one question. (1x2=2)

a. Sound at a distance can be heard distinctly at night than in the day time. Why?

b. Does the frequency of sound produced by an organ pipe change with its diameter? Explain.


a. Explain with proper sketch, the difference between wave front and wavelets.

b. Which parameters of light does not change on refraction?

Group B

5. Attempt any three question. (4x3=12)

a. State Joule’s law of heating and verify it experimentally.

b. State Kirchhoff’s laws. Apply them to obtain the balanced state condition of Wheatstone bridge.

c. What is the principle of potentiometer? How this is used to measure the internal resistance of a cell.

d. Derive expressions for the effective resistance of number of resistors connected in series and parallel.


a. Discuss the motion of an electron in a uniform magnetic field and show that if a free electron moves at right angle to a magnetic field, the path is a circle and the time period of revolution is independent of the speed of the electron.

b. What do you mean by stopping potential? Describe Millikan’s experiment to determine the value of Planck’s constant.

c. Write down the postulates of Bohr’s hydrogen atom. Hence derive expression for energy of the third electron orbit.

d. Explain renewable and non-renewable source of energy with examples. Give an account of the energy consumption scenario in Nepal.


a. What is end correction of a pipe? Describe the different modes of vibration of air column in an organ pipe closed at one end.

b. Describe Newton’s expression for the velocity of sound in a gas with Laplace correction.


a. Describe Huygen’s principle with figure to prove the laws of reflection.

b. Describe Foucault’s method to determine the speed of light.

9. Attempt any two questions. (4x2=8)

a. Resistance of a wire of length 1 m, diameter 1 mm is 2.2 Ω. Calculate its resistivity and conductivity.

b. Two lamps rated 25 W – 220 V and 100 W – 220 V are connected to 220 V supply. Calculate the powers consumed by the lamps.

c. Find the current in 2 Ω register in the given circuit.

Here 𝑉1 = 35 𝑉 , 𝑉2 = 40 𝑉, 𝑅1 = 3Ω , 𝑅2 = 2Ω.


a. An electron having 500 eV energy enters at right angle to a uniform magnetic field of 10−4T. If its specific charge is 1.75x 1011 𝐶𝐾𝑔−1, calculate the radius of its circular orbit.

b. 400 nm wavelength of light falls on a photo sensitive material of work function 2.3 eV. Compute the maximum energy of photoelectrons.

c. A hydrogen atom is in ground state. What is the quantum number to which it will be excited absorbing a photon of energy 12.75 eV ?

11. At what temperature, the velocity of sound in air is increased by 50% to that at 27𝑜𝐶 ? (4)

12. A plane mirror is placed at the centre of a concave mirror having radius of curvature 40m. The plane mirror rotates at the speed of 2600 revolutions per second. Calculate the angle between ray incidents on the plane mirror and then reflected from it after the light has travelled to the concave mirror

and back to the plane mirror. (Speed of light = 3x108 𝑚𝑠−1) (3)

THE END


Subject: Physics Set: B Full Marks: 75



a. Will the drift velocity of electrons change if the diameter of a connecting

wire is halved? Why?

b. Give an example of non-ohmic conductor and present its current voltage

characteristic graph.

c. Two bulbs of 60 W and 100 W are connected in series and the

combination is connected across the mains. Which bulb will glow more

brightly? Give reason.

d. State Kirchoff’s laws of electrical circuits.

e. Does a charged particle moving through a magnetic field experience a

force? Express with conditions maximum and minimum force it

experiences.

f. Explain the difference between resistance and resistivity of a wire.


a. What is the importance of Millikan’s oil drop experiment?

b. The value of e/m is constant for cathode rays but not for positive rays,

why?

c. What is threshold Wavelength? On which factor does it depend.

d. What is work function of a metal? Does it depend on the intensity of

incident light?

e. An electron and proton have the same kinetic energy. Which one of

them has the longer de-Broglie wavelength?

f. “The total energy of an electron of an atom in an orbit is negative”. What

does this negative energy indicate?


a. If you are walking on the moon surface, can you hear the cracking sound

behind you? Explain.

b. Why does sound travel faster in metals than in air?


a. Can Snell’s law be verified from wave theory? Explain with figure only.

b. What is Huygen’s principle?


a. Discuss the mechanism of metallic conduction. Derive a relation

between current through a metallic conductor and drift velocity in terms

of the number of free electrons per unit volume of the conductor.

b. Explain the magnetic effect on a current carrying rectangular coil. Hence obtain expression for the torque on the coil.

c. Define emf, terminal p.d. and internal resistance of a cell. Derive relation between them for the circuit drawing current.

d. What is the principle of potentiometer? How this is used to compare the emf’s of two cells.


a. Verify quantization of charge using Millikan’s oil drop experiment.

b. What is photoelectric effect? Explain the effect of increase of

(i) frequency

(ii) intensity of the incident radiation on photoelectrons emitted by a phototube.

c. What are Bohr postulates? Derive the formula for the radius of the third Bohr’s orbit.

d. What is air pollution? Discuss major sources of air pollution and suggest some ways of controlling it.


a. Discuss the effect of pressure, temperature and density of elastic medium on the velocity of sound.

b. What do you understand by harmonics in the case of organ pipes? Describe the different modes of vibration of air column in an organ pipe open at both ends.


a. What is meant by wave front? Verify Snell’s law on the basis of wave theory.

b. Describe Michelson’s method to determine the speed of light.


a. Two resistors of resistance 1000 Ω and 2000 Ω are joined in series with a 100V supply. What will be the reading on a voltmeter of internal resistance 4000 Ω when placed across (i) 1000 Ω resistor and (ii)

2000 Ω resistor ?

b. A 540 W electric heater is designed to operate from 120 V lines. (a) What is its resistance ? (b) What current does it draw ? (c) If the line

voltage drops to 110 V, what power does the heater take? ( Assume that the resistance is constant.)

c. A simple potentiometer consists of a uniform wire AB, 1 m long, which

has a resistance 2 Ω. The resistance of cells are negligible. If R = 2.4

Ω, what will be the length AC for zero galvanometer deflection?

A C B


a. An electron moves in a circular path of radius 20 cm in a uniform

magnetic field 2𝑥10−3T. Find the speed of the electron and period of

revolution. (Mass of electron = 9.1x10−31𝑘𝑔)

b. The maximum energy of photoelectrons emitted from a metal surface is

1.2 eV. If the threshold wavelength is 2.48X10−9m, calculate the

wavelength of incident light. (Planck’s constant = 6.62x10−34𝐽𝑠)

c. Determine the wavelength of a proton that has been accelerated

through a potential difference of 20 KV. Mass of proton = 1.67x10−27𝑘𝑔.

11. A source of sound of frequency 512 Hz emits waves of wavelength 64.5 cm in air at 20𝑜𝐶. What would be the velocity of sound at 0𝑜𝐶. (4)

12. A beam of light after reflection at a plane mirror, rotating 2000 times per minute, passes to a distant reflector. It returns to the rotating mirror from which it is reflected to make an angle of 1𝑜with its original direction. If the distance between the mirrors is 6250 m, calculate the speed of light. (3)

R

G

4 V

1.5 V

first terminal examination - 2076 zoology (group b) botany ...21. define molarity and mole fraction....

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