# Work Done

## Trending Questions

**Q.**An ideal gas is taken through the cycle A→B→C→A, as shown in the figure. If the net heat supplied to the gas in the cycle is 5 J, the work done by the gas in the process C→A is

- −5 J
- −15 J
- −10 J
- −20 J

**Q.**A sample of an ideal gas in taken through the cyclic process abca as shown in figure. The change in the internal energy of the gas along the path ca is −180 J. The gas absorbs 250 J of heat along the path ab and 60 J along the path bc. The work done by the gas along the abc is

- 120 J
- 130 J
- 100 J
- 140 J

**Q.**P−V diagram of an ideal gas is shown in the figure. Work done by the gas in process ABCD is

- 4P0V0
- 2P0V0
- 3P0V0
- P0V0

**Q.**A thermodynamic system goes from state (i) (P, V) to (2P, V) and (ii) (P, V) to (P, 2V). Work done in the two cases is

- PV, Zero
- PV, PV
- Zero, Zero
- Zero, PV

**Q.**One mole of a monoatomic ideal gas undergoes an adiabatic expansion in which its volume becomes eight times its initial value. If the initial temperature of the gas is 100K and the universal gas constant R = 8.0 Jmol−1K−1, the decrease in its internal energy, in Joule, is

**Q.**

Figure shows the variation in the internal energy U with the volume V of 2.0 mol of an ideal gas in a cyclic process abcda. The temperatures of the gas at b and c are 500 K and 300 K respectively. Calculate the heat absorbed by the gas during the process.

**Q.**A U−ρ (U→ internal energy of the gas and ρ→ density of the gas) plot of an ideal mono-atomic gas undergoing a cyclic process is shown in the figure. A→B is part of a rectangular hyperbola. Then which of the following graphs in the options below corresponds to the process given in the adjacent diagram?

**Q.**A cyclic process for 1 mole of an ideal gas is shown in figure in the V−T diagram. The work done in process AB, BC and CA respectively, are

- 0, 2RT2ln(V1V2), R(T1−T2)
- 0, RT2ln(V2V1), −2R(T1−T2)
- R(T1−T2), 0, RT1lnV1V2
- 0, RT2ln(V2V1), −R(T2−T1)

**Q.**The net work done by the tension in the figure, when the bigger block of mass M touches the ground is

- +Mgd
- −(M+m)gd
- −mgd
- Zero

**Q.**An ideal gas is taken around ABCA as shown in the above P-V diagram. The work done during a cycle is

- 2PV
- PV
- 1/2PV
- Zero

**Q.**List I describes thermodynamic processes in four different systems. List II gives the magnitudes (either exactly or as a close approximation) of possible changes in the internal energy of the system due to the process.

List -I | List -II | ||

(I) | 10–3 kg of water at 100∘C is converted to steam at the same temperature, at a pressure of 105 Pa. The volume of the system changes from 10–6 to 10–3 in the process. Latent heat of water =2250 kJ/kg. | (P) | 2 kJ |

(II) | 0.2 moles of a rigid diatomic ideal gas with volume V at temperature 500 K undergoes an isobaric expansion to volume 3V. Assume R=8.0 J mol−1K−1. |
(Q) | 7 kJ |

(III) | One mole of a monoatomic ideal gas is compressed adiabatically from volume V=13 m3 and pressure 2 kPa to volume V8 | (R) | 4 kJ |

(IV) | Three moles of a diatomic ideal gas whose molecules can vibrate, is given 9 kJ of heat and undergoes isobaric expansion. | (S) | 5 kJ |

(T) | 3 kJ |

Which one of the following options is correct?

- I→S, II→P, III→T, IV→P
- I→Q, II→R, III→S, IV→T
- I→T, II→R, III→S, IV→Q
- I→P, II→R, III→T, IV→Q

**Q.**Consider the cyclic process ABCA as shown in the figure, performed on a sample of 2.0 mole of an ideal gas. A total of 1200 J of heat is withdrawn from the sample in the process. Find the magnitude of the work done (in joules) by the gas during the part BC. (R=8.3 JK−1mol−1)

- 2580 J
- 3625 J
- 4520 J
- 1550 J

**Q.**An ideal gas is taken through a quasi-static process described by P=αV2, with α=5.00 atm/m6. The gas is expanded to twice its original volume of 1.00 m3. How much work is done by the gas (in MJ) during expansion in this process?

**Q.**Figure illustrates a cycle conducted with n moles of an ideal gas. In the states a and b the gas temperature are Ta and Tb respectively. Temperature of the gas in the state c is

- √TaTb
- Ta+Tb
- Ta−TbTa+Tb
- (Ta+Tb)2

**Q.**Two moles of an ideal monoatomic gas at 27∘C occupies a volume of V. If the gas is expanded adiabatically to the volume 23/2V, then the work done by the gas will be (γ=53, R=8.31 J/mol K)

- 3739.5 J
- 2627.23 J
- 2500 J
- −2500 J

**Q.**One mole of an ideal gas is kept enclosed under a light piston of area A=10−2 m2 which is connected to a compressed spring of spring constant 100 N/m. The volume of the gas is 0.83 m3 and its temperature is 100 K. The gas is heated so that it compresses the spring further by 0.1 m. The work done by the gas in the process is: [TakeR=8.3 J/K mol and suppose there is no atmosphere].

- 9 J
- 3 J
- 1.5 J
- 6 J

**Q.**An ideal monoatomic gas is taken around the cycle ABCDA as shown in the PV diagram. The work done during the cycle is given by

- 12PV
- PV
- 2PV
- 4PV

**Q.**

One mole of ideal gas undergoes a linear process as shown in figure below. Its temperature expressed as a function of volume V is.

P0V0R

P0VR

P0VR(1−VV0)

P0VR(1−(VV0)2)

**Q.**One mole of a gas expands with temperature T such that its volume, V=kT2, where k is a constant. If the temperature of the gas changes by 60∘C then the work done by the gas is

- 120R
- R ln 60
- kR ln 60
- 60 kR

**Q.**Two masses, 800 kg and 600 kg, are at a distance 0.25 m apart. Compute the magnitude of the intensity of the gravitational field at a point distant 0.20 m from the 800 kg mass and 0.15 m from the 600 kg mass.

**Q.**

The temperature of n moles of an ideal gas is increased from T to 4T through a process for which pressure where a is constant. The work done by gas is:

nRT

4nRT

2nRT

6nRT

**Q.**A cylinder of ideal gas is closed by an 8 kg movable piston (area 60 cm2). Atmospheric pressure is 105 Pa. When the gas is heated from 30°C to 100°C, the piston rises by 20 cm. The piston is then fixed in its place and the gas is cooled back to 30°C. Let ΔQ1 be the heat added to the gas in the heating process and |ΔQ2| the heat lost during cooling. Then the value of ΔQ1−|ΔQ2| will be

- 0
- 136 J
- −136 J
- −68 J

**Q.**An ideal gas is taken from state A to the state B, as shown in the P−V diagram. The work done in the process is

- (PA−PB)×(VB−VA)
- 12(PB−PA)×(VB+VA)
- 12(PB−PA)×(VB−VA)
- 12(PB+PA)×(VB−VA)

**Q.**Consider an ideal gas having adiabatic exponent γ. In some process, its molar heat capacity varies with temperature as C=αT where α is a constant. The work performed by one mole of the gas during its heating from the temperature of T0 to ηT0 (η>1) is

- α ln[η]−RT∘(η−1)(γ−1)
- 2α ln[η]−RT∘(η−1)(γ−1)
- α ln[η]
- −RT∘(η−1)(γ−1)

**Q.**One mole of diatomic gas at 300 K is compressed adiabatically to one-fourth of its volume. If γ=1.5, the work done on gas will be

- 1280 J
- 1610 J
- 2044 J
- 4986 J

**Q.**One mole of an ideal gas is heated slowly so that it goes from the P−V state (Pi, Vi) to (3Pi, 3Vi) in such a way that the pressure of the gas is directly proportional to the volume. How much work is done on the gas in the process?

- 4PiVi
- 16PiVi
- −9PiVi
- −4PiVi

**Q.**Work done by 0.1 mole of a gas at 27∘C to double its volume at constant pressure is

[Take R=2 cal mol−1K−1]

- 54 cal
- 600 cal
- 546 cal
- 60 cal

**Q.**Find the work done by the system in closed path ABCA as shown below.

- −(p2−p1)(V2−V1)2
- (V1−V2)(p1−P2)
- (p2+p1)(V2−V1)2
- Zero

**Q.**A vertical cylinder piston system has cross-section S. It contains 1 mole of an ideal monatomic gas under a piston of mass M. At a certain instant a heater is switched on which transmits heat q per unit time of the cylinder. Assume the piston is in equilibrium at all times during the process. The velocity v of the piston given the condition that pressure under the piston is constant and the system is thermally insulated is xq5S(Po+MgS). Here the value of x is

**Q.**In an isothermal reversible expansion if the volume of 96 g of oxygen at 27∘C is increased from 70 L of 140 L, then the work done by the gas will be

- 300 R log102
- 2070 R log102
- 900 R log102
- 81 R loge2