Heat, Internal Energy and Work

Figure shows the P-V diagram of an ideal gas undergoing a change of state from A to B. Four different parts I, II, III and IV as shown in the figure may lead to the same change of state.

1. Change in internal energy is same in IV and III cases, but not in I and II.
2. Change in internal energy is same in all the four cases.
3. Work done is maximum in case I
4. Work done is minimum in case II.

Should the internal energy of a system necessarily increase if its temperature is increased?

A force F is applied on a block of mass M. The block is displaced through a distance d in the direction of the force. What is the work done by the force on the block? Does the internal energy change because of this work?

When we rub our hands they become warm. Have we supplied heat to the hands?

Explain given cases related to energy transfer between the system and surrounding –

1. energy transferred (Q) > 0
2. energy transferred (Q) < 0
3. energy transferred (Q) = 0 

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.

In changing the state of a gas adiabatically from an equilibrium state A to another equilibrium state B, an amount of work equal to 22.3 J is done on the system. If the gas is taken from state A to B via a process in which the net heat absorbed by the system is 9.35 cal, how much is the net work done by the system in the latter case? (Take 1 cal = 4.19 J)

Figure shows two processes A and B on a system. Let ∆Q₁ and ∆Q₂ be the heat given to the system in processes A and B respectively. Then ____________ .