1. Mechanics
    2. 1. Units, Dimensions and Errors
    2. Vectors and Scalars
    3. Motion in a Straight Line
    4. Projectile Motion
    5. Newton's Laws of Motion
    6. Friction
    7. Work, Energy, Power and Collision
    8. Circular motion
    9. Rotational motion
    10. Simple Harmonic Motion
    11. Gravitation
    12. Elasticity
    13. Surface Tension
    14. Fluid dynamics and Viscosity
    15. Hydrostatics
  2. Heat and Thermodynamics
    3. 16. Thermometry
    17. Thermal expansion
    18. Calorimetry, Change of State and Hygrometry
    19. Gas Laws and Kinetic theory of Gases
    20. Transmission of Heat
    21. Thermodynamics
  3. Sound and Waves
    4. 22. Wave
    23. Superposition of Waves
    24. Stationary/ Standing waves
    25. Doppler's effect and Musical sound
  4. Optics
    5. 26. Reflection of Plane and Curved Mirrors
    27. Refraction at Plane surfaces and Total internal reflection
    28. Refraction through prism and Dispersion of Light
    29. Refraction through Lenses
    30. Chromatic abberation in Lenses, Optical instruments and Human eye
    31. Velocity of Light
    32. Photometry
    33. Wave nature of Light
  5. Electrostatics
    6. 34. Charge and Force
    35. Electric Field and Potential
    36. Capacitance
  6. Electrodynamics
    7. 37. Electric current
    38. Heating Effect of Current
    39. Thermoelectricity
    40. Chemical effect of Current
    41. Meters
  7. Electromagnetism
    8. 42. Properties of Magnets
    43. Magnetic effects of Current
    44. Electromagnetic induction
    45. Alternating current
  8. Modern Physics
    9. 46. Cathode rays, Positive rays and Electrons
    47. Photoelectric effect
    48. X-rays
    49. Atomic structure and Spectrum
    50. Radioactivity
    51. Nuclear physics
    52. Semiconductor and Semiconductor devices
    53. Diode and Triode valves
    54. Logic gates
    55. Relativity and Universe
    56. Particle physics
Heat and Thermodynamics
21. Thermodynamics
1. An inventor claims to have made an engine which consumes 1g of fuel per second (of calorific value 2 K cal/gm) and delivers 10 KW of power. Mark the correct statement

[BP 2010]

  • This is impossible.
  • This possible.
  • The possibility of invention is determined by design of engine.
  • The possibility of invention is determined by nature of fuel used.
2. Two identical containers A and B with frictionless pistons contain the same ideal gas at the same temperature and volume V. The mass of gas in A is mA, and that in B is mB. The gas in each cylinder is now allowed to expand isothermally to the same final volume 2V. The change in pressure in A and B are found to be ΔP and 1.5ΔP respectively. Then:

[BP 2009]

  • 4mA = 9mB
  • 2mA = 3mB
  • 3mA = 2mB
  • 9mA = 4mB
3. The pressure and volume are changing but the temperature is constant in the process:

[IOM 2012]

  • Adiabatic
  • Isothermal
  • Isobaric
  • Isochoric
4. A refrigerator has to transfer an average of 263J of heat per second from -10°C to 25°C. The average power consumed by the refrigerator is

[IOM 2010/2009]

  • 10 W
  • 20 W
  • 35 W
  • 40 W
5. If a gas is allowed to expand adiabatically against external pressure:

[MOE 2009]

  • Its temperature remains constant.
  • Pressure remains constant.
  • There is increase in internal energy.
  • There is decrease in internal energy.
6. Efficiency of Carnot engine working between 27°C and 127°C is

[MOE 2011]

  • 50%
  • 100%
  • 25%
  • 75%
7. In a Carnot engine, the temperature of the heat sink is 27°C and that of the source is 327°C. The efficiency is:

[MOE 2012]

  • 50%
  • 91%
  • 95%
  • 75%
8. One mole of an ideal gas with γ = 1.4 is adiabatically compressed so that its temperature rises from 27°C to 35°C. The change in internal energy of the gas is

[MOE 2012]

  • -166 J
  • 166 J
  • -168 J
  • 168 J
9. The efficiency of a Carnot engine is 1/5. On reducing the temperature of sink by 45°C, efficiency becomes 1/3. The initial temperature of the sink was

[MOE 2014]

  • 270 K
  • 310 K
  • 337 K
  • 540 K
10. The efficiency of a Carnot engine is 20%. On reducing the temperature of sink by 45°C, efficiency becomes 33.3%. The initial temperature of the sink was

[MOE 2014]

  • 270 K
  • 310 K
  • 337 K
  • 540 K
11. In an isothermal condition

[KU 2014]

  • Heat given by surrounding is equal to work done.
  • Heat given by surrounding is equal to internal energy.
  • There is no heat loss to the surrounding.
  • All
12. If 1500 cal of heat is supplied to a system and 1000 J of work is done, what is the increase in internal energy?

[IOM 2014]

  • 2000 J
  • 5000 J
  • 4300 J
  • 5300 J
13. What happens in adiabatic process?

[KU 2013]

  • Volume remains constant.
  • Pressure remains constant.
  • Temperature remains constant.
  • The system is insulated from the surrounding.
14. A Carnot engine kept at temperature at 800K and 400K, the output of cycle is 800J. Then the energy supplied by the source is

[KU 2013]

  • 800 J
  • 1200 J
  • 1600 J
  • 1500 J
15. In an isothermal process

[KU 2009]

  • Pressure remains constant.
  • Thermal energy remains constant.
  • Volume remains constant.
  • Temperature remains constant.
16. During adiabatic compression of 5 moles of gas, 250 J work was done, the change in internal energy will be:

[IE 2012]

  • 150 J
  • -150 J
  • 250 J
  • -250 J
17. The equation of adiabatic process is

[IE 2012]

  • ΔQ = nCPΔT
  • ΔQ = nCVΔT
  • ΔU = nCVΔT
  • ΔU = nCPΔT
18. A Carnot engine with efficiency η=10% works same as heat engine, it is made to work with refrigerator having work done =10J. The heat transferred is

[TE 2013]

  • 10 J
  • 90 J
  • 1 J
  • 100 J
19. If a gas is allowed to expand adiabatically against external pressure

[MOE 2009]

  • Its temperature remains constant
  • Pressure remains constant
  • There is increase in internal energy
  • There is decrease in internal energy
20. A Carnot engine takes in 3000 kcal of heat from a reservoir at 627°C and gives it to a sink at 27°C. The work done by the engine is

[MOE 2010]

  • 4.2 × 106 J
  • 8.4 × 106 J
  • 16.8 × 106 J
  • 0
21. The specific heat capacity of an ideal gas under isothermal condition is

[IOM 1997]

  • 0
  • 8.31
  • ∞
  • 1
22. Which of the following is not correct?

[IOM 1997]

  • In an adiabatic condition, the system is allowed to undergo changes in thermal isolation from the surroundings.
  • In an isothermal condition, heat enters and leaves the system.
  • Adiabatic process is accompanied by change in temperature and is quick.
  • It is possible to cool a gas to absolute zero temperature.
23. Find out the work done from the graph:

[Graph-based question]

  • 12 PV
  • 6 PV
  • 3 PV
  • PV
24. If one mole of an ideal gas at STP is heated through 1K, the work done by the gas in heat unit will be

[MOE Curriculum]

  • 1.98 cal
  • 8.31 cal
  • 0.831 cal
  • 83.1 cal
25. A Carnot engine takes 300 calories of heat from a source at 500K and rejects 150 calories of heat to the sink. The temperature of the sink is

[MOE 2065]

  • 400 K
  • 250 K
  • 150 K
  • 100 K
26. The maximum efficiency of an engine operating between 30°C and 300°C is

[MOE 2061]

  • 4.71%
  • 47.1%
  • 90%
  • 9%
27. An inflated tyre of a bicycle bursts. Which of the following relation between pressure P and temperature T holds good if γ is the ratio of the specific heats of air?

[MOE 2000]

  • PγT = constant
  • Pγ-1T-γ = constant
  • P1-γTγ = constant
  • PγT1-γ = constant
28. When a gas undergoes adiabatic expansion, its internal energy:

[KU 2008]

  • Increases
  • Decreases
  • Remains same
  • None
29. Internal energy of an ideal gas depends on

[KU 2008]

  • Volume and temperature
  • Pressure and temperature
  • Volume only
  • Temperature only
30. A Carnot engine has the same efficiency between 800K and 500K and xK to 600K. The value of x is

[IE 2004]

  • 1000 K
  • 960 K
  • 846 K
  • 754 K
31. Two steam engines A and B, A working between temperature 650K and 700K and another B working between temperature 300K and 350K. Then

[Bangladesh 2009]

  • A is more efficient than B
  • A is less efficient than B
  • A and B are equal efficient
  • Efficiency independent upto temperature