Science (English Medium) Class 11 - CBSE Question Bank Solutions for Physics

Refer to figure. Let ∆U₁ and ∆U₂ be the changes in internal energy of the system in the process A and B. Then _____________ .

Consider the process on a system shown in figure. During the process, the work done by the system ______________ .

Consider the following two statements.

(A) If heat is added to a system, its temperature must increase.

(B) If positive work is done by a system in a thermodynamic process, its volume must increase.

An ideal gas goes from the state i to the state f as shown in figure. The work done by the gas during the process ______________ .

Consider two processes on a system as shown in figure.

The volumes in the initial states are the same in the two processes and the volumes in the final states are also the same. Let ∆W₁ and ∆W₂ be the work done by the system in the processes A and B respectively.

A gas is contained in a metallic cylinder fitted with a piston. The piston is suddenly moved in to compress the gas and is maintained at this position. As time passes the pressure of the gas in the cylinder ______________ .

The pressure p and volume V of an ideal gas both increase in a process.

(a) Such a process is not possible.

(b) The work done by the system is positive.

(c) The temperature of the system must increase.

(d) Heat supplied to the gas is equal to the change in internal energy.

In a process on a system, the initial pressure and volume are equal to the final pressure and volume.

(a) The initial temperature must be equal to the final temperature.

(b) The initial internal energy must be equal to the final internal energy.

(c) The net heat given to the system in the process must be zero.

(d) The net work done by the system in the process must be zero.

A 100 kg lock is started with a speed of 2.0 m s⁻¹ on a long, rough belt kept fixed in a horizontal position. The coefficient of kinetic friction between the block and the belt is 0.20. (a) Calculate the change in the internal energy of the block-belt system as the block comes to a stop on the belt. (b) Consider the situation from a frame of reference moving at 2.0 m s⁻¹ along the initial velocity of the block. As seen from this frame, the block is gently put on a moving belt and in due time the block starts moving with the belt at 2.0 m s⁻¹. calculate the increase in the kinetic energy of the block as it stops slipping  past the belt. (c) Find the work done in this frame by the external force holding the belt.

Figure shows three paths through which a gas can be taken from the state A to the state B. Calculate the work done by the gas in each of the three paths.

Let T_a and T_b be the final temperatures of the samples A and B, respectively, in the previous question.

A gas is taken through a cyclic process ABCA as shown in figure. If 2.4 cal of heat is given in the process, what is the value of J ?

A substance is taken through the process abc as shown in figure. If the internal energy of the substance increases by 5000 J and a heat of 2625 cal is given to the system, calculate the value of J.

A gas is taken along the path AB as shown in figure. If 70 cal of heat is extracted from the gas in the process, calculate the change in the internal energy of the system.

A gas is initially at a pressure of 100 kPa and its volume is 2.0 m³. Its pressure is kept constant and the volume is changed from 2.0 m³ to 2.5 m³. Its Volume is now kept constant and the pressure is increased from 100 kPa to 200 kPa. The gas is brought back to its initial state, the pressure varying linearly with its volume. (a) Whether the heat is supplied to or extracted from the gas in the complete cycle? (b) How much heat was supplied or extracted?

Figure shows a cylindrical tube of volume V with adiabatic walls containing an ideal gas. The internal energy of this ideal gas is given by 1.5 nRT. The tube is divided into two equal parts by a fixed diathermic wall. Initially, the pressure and the temperature are p₁, T₁ on the left and p₂, T₂ on the right. The system is left for sufficient time so that the temperature becomes equal on the two sides. (a) How much work has been done by the gas on the left part? (b) Find the final pressures on the two sides. (c) Find the final equilibrium temperature. (d) How much heat has flown from the gas on the right to the gas on the left?

Given a + b + c + d = 0, state whether the following statement is correct or incorrect: 

The magnitude of (a + c) equals the magnitude of (b + d).

Given a + b + c + d = 0, state whether the following statement is correct or incorrect: 

The magnitude of a can never be greater than the sum of the magnitudes of b, c, and d. 

Two cylinders A and B of equal capacity are connected to each other via a stopcock. A contains a gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stopcock is suddenly opened. Answer the following:

What is the final pressure of the gas in A and B?

Two cylinders A and B of equal capacity are connected to each other via a stopcock. A contains a gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stopcock is suddenly opened. Answer the following:

What is the change in internal energy of the gas?