BSc Physics SEM III 2019 2020 Oct 2020 PHYSICS PAPER I Question Paper - Mumbai University | munotes

Questions asked in this paper

• ii) figures to the right indicate full marks

1. Q1 A) Select the correct option (12M)
2. Q1 The highest velocity attained by a rocket is
3. Q2 Oscillation are damped due to 3)A Carnot engine whose temperature of the source is 400K takes 200 calories of heat at this temperature and rejects 150 calories of heat to the sink. The temperature of sink is
   • i)320K ii1)220K iv)200K 4)The unit of entropy ts
   • i) iii) iv) 5)A reversible heat engine can be 100% efficient if the temperature of the sink 1s
   • i)0"c ii) less than that of source iil) iv)equal to that of source 6)Liquid traasition at 2.17K called point
   • i) Below A point helium is called helium-I
   • ii)Above point helium is called helium-II
   • iii) Below 2 point helium is called
4. Q1 B) Answer in one sentence. (3M)
   • i)Give the Expression for time period of compound pendulum
   • ii)Draw T-S diagram for a reversible Carnot cycle Diesel and Otto engine have same compression ratio then which one is more efficient?
5. Q1 Energy of damped harmonic oscillator decreases . with time
6. Q2 The equation of motion of a body is acceleration of the body Z
7. Q3 The process in the porous plug experiment
8. Q4 In Diesel engine the heat is absorbed at constant
9. Q5 The entropy can be created but it IS
10. Q2 A) Answer the following questions.(ANY 1) (8M)
    • i)Show that when two perpendicular linear simple harmonic motion of the same amplitude and frequency but differing in phase by are superposed, the resultant motion is a uniform circular
    • ii) Show that the total angular momentum of a system of particle is equal to the angular momentum of its center of mass plus angular momentum due to its motion about the center of
11. Q2 B) Answer the following questions.(ANY 1) (8M)
    • i) What is compound pendulum? Set up the equation of motion of acompound pendulum and obtain an expression for its time period
    • ii) Set up the equation of motion of a driven damped oscillator ‘Comment on nature of equation and the solution
12. Q2 C) Answer the following questions.(ANY 1) (4M)
    • i) Four masses and 4Kg are located at respectively . Find the center of mass of this system
    • ii)A rocket is initially moving with a speed of 2500 m/s. If its exhaust velocity is m/s. what fraction of its mass will exist when its mass will exhaust when its velocity is 4500m/s?
13. Q3 A) Answer the following questions.(ANY 1) (8M)
14. Q1 State and prove Carnot’s theorem
15. Q2 Explain the concept of Entropy. Hence show that for any reversible or irreversible
16. Q3 B) Answer the following questions.(ANY 1) (8M)
17. Q1 Derive an expression for entropy of a perfect gas in terms of its temperature and
18. Q2 Derive the expression of efficiency for Carnot’s engine in terms of temperature
19. Q3 C) Answer the following questions.(ANY 1) (4M)
20. Q1 Find efficiency of a Carnot engine working between 127 and 27 It absorbs Calories of heat. How much heat is rejected? 2)State second law of thermodynamics in various forms 80 marks
21. Q4 A) Answer tie following questions.(ANY 1) (8M)
22. Q1 Explain the construction and working of otto engine with neat labeled diagram
23. Q2 Describe loule’s experiment. What was the outcome of it?
24. Q4 B) Answer the following questions.(ANY 1) (8M)
25. Q1 Explain the porous plug experiment. What are its result? Is the process reversible or
26. Q2 Derive the Maxwell thermodynamic relation Answer the following questions.(ANY 1) (4M)
27. Q1 In double acting steam engine the average pressure of steam is 1.2 x the length of a stroke is 1m and the area of piston is 0.15 sqm . Find the power of the engine if it makes 4 strokes per second
28. Q2 Write the uses of Liquid Helium
29. Q5 Answer the following questions.( Any 4) (20 M)
30. Q1 Find the centre of mass uniform thin circular ring
31. Q2 A Carnot engine whose lower temperature heat sink is at has its efficiency 40%.What is the temperature of heat source? By how much should the temperature of the source increased if the efficiency is to be raised to 70%
32. Q3 Distinguish between otto engine and Diesel engine
33. Q4 When 100 g of water is heated from to find by how much does the entropy of water changes? Given : specific heat of water S=1 cal/gm-K any five properties of liquid helium
34. Q6 Derive the relation between inversion, Boyle and critical temperature

Read from the scan above, so a character or two may differ. The scan is the original.