alphonsa complimentarey physics -1q.p.doc

7/25/2019 ALPHONSA Complimentarey physics -1Q.P.doc

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Alphonsa arts & Science college

B.SC. PROGRAMME IN PHYSICS

I Semester B.Sc egree E!amination "Septem#er $%'

Complimentar( Co)rse " PHI C %* Properties o+ matter & ,hermo-(namics

,ime* $ ho)rs ,otal Mars* '%

Section A

/Ans0er all 1)estions. Each 1)estion carries mar2

1. The change in internal energy of a gas is directly proportional to :

(a) Change in volume.

(b) Change in pressure.

(c) Change in temperature. (d) None of this.

2. What is the efficiency of a Carnots engine !or"ing bet!een the steam point and ice point# (a) 1$$% (b) 2&% (c) '%. n indicator diagram is a graph bet!een *********************.

+. The area under ,- diagram gives ***********************.

(+1 /+ mar"s)

Section B

/Ans0er all 1)estions. Each 1)estion carries $ mars. Ans0er in one or t0o sentences2

0. tate the first la! of thermo dynamics.'. What is a uasi static process#

&. 3ive three eamples of thermodynamic systems (2 /' mar"s)

Section C

/Ans0er an( 3 1)estions. Each 1)estion carries 4 mars. Ans0er in one paragraph2

4. tate the second la! of thermodynamics.5. What is a cyclic process# Calculate the !or" done in a cyclic process.

1$. 6plain the concept of reversible and irreversible processes.

11. 7erive an epression for !or" done in an isothermal process.

(+ /12 mar"s)

Section

/Ans0er to an( 3 pro#lems. Each 1)estion carries 4 mars.2

12. 7erive 8ayers relation using first la! of thermo dynamics.1. The given gas at .T., is suddenly compressed to 192 of its original volume. ind the

resulting pressure if the ratio of specific heat capacities of the gas / 09

1+. ;ne mole of a gas at 2&$C is isothermally epanded to double its volume. Calculate the !or"done by the gas . < / 4. =mol*1>*1.

10. Carnots engine !hose source is at 12&$C ta"es in +2$$ ?oules of heat in each cycle and


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gives out 25+$ ?oules of heat to the condenser. ind the temperature of the condenser.

1' . company claims to have developed an engine !or"ing bet!een the temperatures 22&$Cand 10$C having an efficiency of +0%. Comment on this claim.

(+ /12 mar"s)

Section E

/Ans0er all 1)estions. Each 1)estion carries 5 mars. Ans0er in a#o)t t0o pages21+. What is a Carnots cycle# 7erive the efficiency of a Carnots reversible heat engine#

10. What is an adiabatic process# 7erive an epression for !or" done in an adiabatic process.

(24 /1' mar"s)

FIRST SEMESTER B.Sc. DEGREE EXAMINATION, January 2016

(CUCBCSS-UG)

Complementary CoursePhysics

PH 1C01PROPERTIES OF MATTER AND THERMODYNAMICS

Time: Three Hours Maximum :

64 Marks

Section A

Answer all questions.Each question carries 1 mark.

1. If the work done in stretching a wire by 1 mm is 2 J, the work necessary for stretching

another

wire of the same material but double the radius and half the length by 1 mm is

--------------------------------------------------------------------------------------------------------------------------

.

2. A wire can support a load W without breaking. It is cut into two equal parts. The

maximum load

that each part can support is-------------.

3. The viscous drag on a small spherical body moving with a speedvis proportional to--------------.

4. When the body attain terminal velocity its acceleration is-------------.

5. In a capillary tube, water rises to a height of 4 cm. If the cross-sectional area of the tube

wereone-fourth, water would have risen to a height of---------------.

6 A Carnot engine works first between 327 C and 27 C, The efficiency is .

.

7 Mean free path of the molecule of a gas depends on the molecular diameterdas--------------

.

8 The ratio of the two specific heats of a diatomic gas is (a) 1.66 (b) 1.4 9c0 1.33 (d) 1.21 .


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9. In a complete Carnot cycle ,the change in entropy of the universe is 9a) positive (b)

negative (c) infinite

(d) zero

10. Give an example of thermodynamic system.(10 x 1 = 10 marks)

SectionB

Answer all seven questions.Each question carries 2 marks.

11 State Hookes law.*

12 Out of the stress and strain, which is the cause and effect? Why ?

13What is meant by elastic hysteresis?

14What is the significance of Stokes formula. What is its use?

15State and explain First law of thermodynamics

16Why do gases have two specific heats?

17How does pressure effect the melting point of a substance?

(7 x 2 = 14

marks)Section C

Answer any three questions.Each question carries 4 marks.

18 Explain why steel is more elastic than rubber

19 Define the three medullae of elasticity and poissons ratio.

20 Discuss the various factors which control surface tension of a liquid.

21 Derive Claussius- Clapyeron equation

22 State and explain the principle of increase of entropy.

(3 x 4 = 12marks)

SectionD

Answer any three problems.Each problem carries 4 marks.

23 A solid sphere of mass 3 kg and diameter 0.2 m is suspended from a wire. The torque

required to

twist the wire is 5 x 10~2Nm/radian. Calculate the period of oscillation.

24 A metal plate 5 cm x 5 cm rests on layer of castor oil 1 mm thick whose coefficient of

viscosity is

1.55 NS m~2. Find the horizontal force required to move the plate with a speed of 2

em/s.

25 Calculate the amount of energy evolved when 8 droplets of water of surface tension


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0.072 N/m and

radius 0.5 mm each combine into one.

26 Calculate the change in entropy of a system contains 1 kg ice at 0 C, which melts at

the same

temperature. Latent heat of ice 79.6 k cal/kg.

27 Calculate the change in boiling point of water when the pressure is increased by 1

atmosphere.

B.P of water is 373 K. Specific volume of steam 1.671 m3and Latent heat of steam

2.268 x 106J

kg -1.

(3 x 4 = 12marks)

Section E

Answer any two problems.Each problem carries 8 marks.

28 Define a cantilever. With necessary theory explain how a cantilever can be used to find the

Youngs

modulus29 Derive Poiseullies formula.

30 Explain the concept of reversible and irreversible process. Show that the efficiency

of a

reversible engine is maximum

31 Explain thermodynamic potentials. Derive Maxwells thermodynamic relations.

(2 x 8 = 16marks)

alphonsa complimentarey physics -1q.p.doc

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