Thermodynamics CBSE Questions & Answers

Thermodynamics

This is Physics Class 11 Thermodynamics CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
One mole of an ideal gas is heated slowly so that it goes from PV state (\({{\rm{P}}_{\rm{i}}}\) , \({{\rm{V}}_{\rm{i}}}\)) to (3 \({{\rm{P}}_{\rm{i}}}\), 3 \({{\rm{V}}_{\rm{i}}}\)) in such a way that the pressure of the gas is directly proportional to the volume. How much work is done in the process?
  • A
    \({{\rm{P}}_{\rm{i}}}\) \({{\rm{V}}_{\rm{i}}}\)
  • B
    4 \({{\rm{P}}_{\rm{i}}}\) \({{\rm{V}}_{\rm{i}}}\)
    Correct
  • C
    3 \({{\rm{P}}_{\rm{i}}}\) \({{\rm{V}}_{\rm{i}}}\)
  • D
    2 \({{\rm{P}}_{\rm{i}}}\) \({{\rm{V}}_{\rm{i}}}\)
2
One mole of an ideal gas is heated slowly so that it goes from PV state (\({{\rm{P}}_{\rm{i}}}\) , \({{\rm{V}}_{\rm{i}}}\)) to (3 \({{\rm{P}}_{\rm{i}}}\) , 3 \({{\rm{V}}_{\rm{i}}}\)) in such a way that the pressure of the gas is directly proportional to the volume. How is the temperature of the gas related to its volume during this process?
  • A
    \(T = \left( {{{{P_i}} \over {nR{V_i}}}} \right){V^3}\)
  • B
    \(T = \left( {{{4{P_i}} \over {nR{V_i}}}} \right){V^2}\)
  • C
    \(T = \left( {{{{P_i}} \over {nR{V_i}}}} \right){V^2}\)
    Correct
  • D
    \(T = \left( {{{2{P_i}} \over {nR{V_i}}}} \right){V^2}\)
3
An ideal gas is enclosed in a cylinder with a movable piston on top. The piston has a mass of 8 000 g and an area of 5.00 \({\rm{c}}{{\rm{m}}^{\rm{2}}}\) and is free to slide up and down, keeping the pressure of the gas constant. How much work is done as the temperature of 0.200 mol of the gas is raised from 20.0\(^\circ \) C to 300\(^\circ \)C?
  • A
    486 J
  • B
    476 J
  • C
    456 J
  • D
    466 J
    Correct
4
A gas expands from I to F along three possible paths, as indicated in Figure. Calculate the work in joules done by the gas along the paths IAF, IF, and IBF
Question 4 figure 1
  • A
    840 J, 536 J, 233 J
  • B
    830 J, 526 J, 223 J
  • C
    810 J, 506 J, 203 J
    Correct
  • D
    820 J, 516 J, 213 J
5
A thermodynamic system undergoes a process in which its internal energy decreases by 500 J. If, at the same time, 220 J of work is done on the system, what is the energy transferred to or from it by heat?
Question 5 figure 1
  • A
    Q = -720 J
    Correct
  • B
    Q = -740 J
  • C
    Q = -730 J
  • D
    Q = -700 J
6
Consider the cyclic process depicted in Figure If Q is negative for the process BC, and if \(\Delta {{\rm{E}}_{{\rm{int}}}}\) is negative for the process CA, what are the signs of Q, W, and \(\Delta {{\rm{E}}_{{\rm{int}}}}\) that are associated with BC?
Question 6 figure 1
  • A
    -, 0, -
    Correct
  • B
    +, 0, -
  • C
    -, +, -
  • D
    -, 0, +
7
Consider the cyclic process depicted in Figure If Q is negative for the process BC, and if \(\Delta {{\rm{E}}_{{\rm{int}}}}\) is negative for the process CA, what are the signs of Q, W, and \(\Delta {{\rm{E}}_{{\rm{int}}}}\) that are associated with CA?
Question 7 figure 1
  • A
    +, 0, -
  • B
    -, -, -
    Correct
  • C
    -, 0, +
  • D
    -, +, -
8
Consider the cyclic process depicted in Figure If Q is negative for the process BC, and if \(\Delta {{\rm{E}}_{{\rm{int}}}}\) is negative for the process CA, what are the signs of Q, W, and \(\Delta {{\rm{E}}_{{\rm{int}}}}\) that are associated with AB?
  • A
    -, +, -
  • B
    -, 0, +
  • C
    +, 0, -
  • D
    +, +, +
    Correct
9
An ideal gas initially at 300 K undergoes an isobaric expansion at 2.50 kPa. If the volume increases from 1.00 \({{\rm{m}}^{\rm{3}}}\) to 3.00 \({{\rm{m}}^{\rm{3}}}\) and if 12.5 kJ of energy is transferred to the gas by heat, what is the change in its internal energy?
  • A
    7.70 kJ
  • B
    7.80 kJ
  • C
    7.50 kJ
    Correct
  • D
    7.60 kJ
10
An ideal gas initially at 300 K undergoes an isobaric expansion at 2.50 kPa. If the volume increases from 1.00 \({{\rm{m}}^{\rm{3}}}\) to 3.00 \({{\rm{m}}^{\rm{3}}}\) and if 12.5 kJ of energy is transferred to the gas by heat, what is the change in its final temperature?
  • A
    950 K
  • B
    800 K
  • C
    900 K
    Correct
  • D
    850 K
11
A 2.00-mol sample of helium gas initially at 300 K and 0.400 atm is compressed isothermally to 1.20 atm. Assuming the behavior of helium to be that of an ideal gas, find the final volume of the gas
  • A
    0.041 \({{\rm{m}}^{\rm{3}}}\)
    Correct
  • B
    0.042 \({{\rm{m}}^{\rm{3}}}\)
  • C
    0.040 \({{\rm{m}}^{\rm{3}}}\)
  • D
    0.039 \({{\rm{m}}^{\rm{3}}}\)
12
A 2.00-mol sample of helium gas initially at 300 K and 0.400 atm is compressed isothermally to 1.20 atm. Assuming the behavior of helium to be that of an ideal gas, find the work done by the gas.
  • A
    -5.28 kJ
  • B
    -5.38 kJ
  • C
    -5.58 kJ
  • D
    -5.48 kJ
    Correct
13
A 2.00-mol sample of helium gas initially at 300 K and 0.400 atm is compressed isothermally to 1.20 atm. Assuming the behavior of helium to be that of an ideal gas, find the energy transferred by heat
  • A
    -5.28 kJ
  • B
    -5.38 kJ
  • C
    -5.58 kJ
  • D
    -5.48 kJ
    Correct
14
An ideal gas is carried through a thermodynamic cycle consisting of two isobaric and two isothermal processes, as shown in Figure. net work done in the entire cycle is given by the equation
Question 14 figure 1
  • A
    \({W_{net}} = R{P_1}\left( {{V_2} - {V_1}} \right)\ln {{{P_2}} \over {{P_1}}}\)
  • B
    \({W_{net}} = {P_1}\left( {{V_2} + {V_1}} \right)\ln {{{P_2}} \over {{P_1}}}\)
  • C
    \({W_{net}} = {P_1}\left( {{V_2} - {V_1}} \right)\)
  • D
    \({W_{net}} = {P_1}\left( {{V_2} - {V_1}} \right)\ln {{{P_2}} \over {{P_1}}}\)
    Correct
15
Find the efficiency of a heat engine that absorbs 2 000 J of energy from a hot reservoir and exhausts 1 500 J to a cold reservoir.
  • A
    30 percent
  • B
    35 percent
  • C
    25 percent
    Correct
  • D
    20 percent