Question

When the gas is heated at constant volume, the heat supplied increases the internal energy of the gas.

• A. True
• B. False

Answer 1

The correct option is A True

When you add heat to a constant volume of gas, the temperature goes up. So does the pressure. Now suppose you let that volume expand a little and let the pressure push outwards until you get back to the starting pressure. The gas will cool down a little as it does that work. It's now at a condition as though you had added the heat at constant pressure. You've added the same heat as when you held the volume fixed, but this time, it's not as hot because some of that heat got converted to mechanical work. So you need to add more heat at constant pressure to get the same increase in temperature that you got in the first place at constant volume.