# Work

## Trending Questions

**Q.**What is the change in internal energy for an isothermal process?

**Q.**The specific heat of hydrogen gas at constant pressure is CP=3.4×103cal/kg∘C and at constant volume is Cr=2.4×103 cal/kg∘C If one kilogram hydrogen gas is heated from 10∘ to 20∘ at constant pressure, the external work done on the gas to maintain it at constant pressure is

**Q.**The P-V diagram of 2 gm of helium gas for a certain process A → B is shown in the figure. what is the heat given to the gas during the process A → B

**Q.**

The pressure of a gas changes linearly with volume from 10 kPa, 200 cc to 50 kPa. 50 cc.

(a) Calculate the work done by the gas.

(b) If no heat is supplied or extracted from the gas, what is the change in the internal energy of the gas ?

**Q.**The total work done on a Particle is equal to the change in its kinetic energy

- Always
- Only if the forces acting on it are conservative.
- Only if gravitational force acts on it.
- Only if Elastic Force acts on it.

**Q.**If the kinetic energy of a satellite orbiting around the earth is doubled, then

- the satellite will escape into the space.
- the satellite will fall down on the earth.
- radius of its orbit will be doubled.
- radius of its orbit will become half.

**Q.**

If the heat 110 J is added to a gaseous system and it acquires internal energy of 40 J, then the amount of internal work done is

- 150 J
- 40 J
- 110 J
- 70 J

**Q.**540 calories of heat convert 1 cc of water at 100∘C to 1670 cc steam at 100∘C at a pressure of 1 atm. Then the work done against the atmospheric pressure is nearly (Take atmospheric pressure, P=1.01×106 dyne/cm2)

- 40 cal
- 30 cal
- 10 cal
- 16.7 cal

**Q.**540 calories of heat convert 1 cubic centimeter of water at 100∘C into 1671 cubic centimeter of steam at 100∘C at a pressure of one atmosphere. Then the work done against the atmospheric pressure is nearly

- 540 cal
- 40 cal
- Zero cal
- 500 cal

**Q.**The equation of state for a gas is given by PV=nRT+αV, where n is the number of moles and α is a positive constant. The initial pressure and temperature of 1 mole of the gas contained in a cylinder are P0 and T0 respectively. The work done by the gas when its temperature doubles isobarically is

- W=P0RT0P0−α
- W=RT0P0−α
- W=2P0RT0P0−α
- W=P0RT02(P−α)

**Q.**A gas expands with temperature according to the relation V=kT2/3. What is the work done, when the temperature changes by 30∘C?

- 20R
- 30R
- 10R
- 40R

**Q.**A block of mass 2 kg is free to move along the x-axis. It is at rest and from t = 0 onwards it is subjected to a time-dependent force F(t) in the x direction. The fore F(t) varies with t as shown in the figure. The kinetic energy of the block after 4.5 seconds is

(F)t

**Q.**

$1$-mole atom of diatomic gas at NTP will be $11.2\mathrm{L}$ liters.

**Q.**A vessel contains 14 g of nitrogen gas at a temperature of 27∘C. The amount of heat to be transferred to the gas to double the r.m.s speed of its molecules will be:

Take R=8.32 J mol–1 K–1.

- 5616 J
- 9360 J
- 2229 J
- 13104 J

**Q.**Internal energy of a non - ideal gas depends upon

- Pressure
- Volume
- All of these
- Temperature

**Q.**The adiabatic Bulk modulus of a perfect gas at pressure P is given by

- P
- 2P
- P/2
- γP

**Q.**

**Which of the following is zero for an isochoric process?**

**Volume****Temperature****Pressure****None of the above**

**Q.**

A gas expands 0.25m3 at constant pressure 103N/m2, the work done is

2.5 ergs

250 J

250 W

250 N

**Q.**A square coil of side l carries a current I. It is kept on a smooth horizontal surface. A uniform magnetic field exists in the region, directed in the plane of the coil as shown in the figure. what should be the minimum value of B, so that the coil will start tipping over ? Mass of the coil is M and it has N number of turns.

- mg2NIl
- MgNIl
- MgNIl2
- Mg2NIl2

**Q.**An ideal gas is made to go through a cyclic thermodynamic process in four steps. The amount of heat involved are Q1=600 J, Q2=−400 J, Q3=−300 J and Q4=200 J respectively. The corresponding work involved are W1=300 J, W2=−200 J, W3=−150 J and W4.

What is value of W4?

- −50 J
- 100 J
- 150 J
- 50 J

**Q.**A gas has molar heat capacity C=37.35 J mol−1K−1 in the process PT=constant. Find the number of degrees of freedom of molecules in the gas.

- 4
- 5
- 2
- 3

**Q.**

The average translational energy and the rms speed of molecules of a sample of oxygen gas at 300 k are

6.21 × 10−21 J and 484 ms−1 respectively. The corresponding values at 600 K are nearly (assuming ideal

gas behavior)

**Q.**A perfect gas contained in a cylinder is kept in vacuum. If the cylinder suddenly bursts, then the temperature of the gas

- decreases
- becomes zero
- remains constant
- increases

**Q.**

A man rowing a boat upstream is at rest with respect to the shore, is he doing work?

**Q.**

In an isothermal expansion

Internal energy of the gas decreases

Internal energy of the gas increases

Average kinetic energy of gas molecule decreases

Internal energy remains unchanged

**Q.**Figure shows the force versus displacement graph of the particle. Find out the work done by the force to displace the particle from x=0 to x=20 m.

- 150 Nm
- 250 Nm
- 200 Nm
- 100 Nm

**Q.**Two Carnot heat engines are put in series such that heat rejected by one engine is used in the second engine as heat input. If efficiency of first engine is 30%, and overall combination has efficiency of 65%, then the efficiency of second engine is

- 20%
- 35%
- 40%
- 50%

**Q.**

An accelerated electron has energy of $9.6x{10}^{-18}J$. Express the energy in electron volts (eV)

**Q.**

Work done by a system under isothermal change from a volume V1 to V2 for a gas which obeys Vander Waals equation (V−βn)(P+αn2V)=nRT

**Q.**A coolie is walking on a horizontal platform with a load placed on his head. The mass of load is 5 kg. If the coolie travels a distance of 10 m, the workdone by him on the load is :

- 500 J
- 500 J
- zero
- 1000 J