Physics 221 Worksheet: Chapter 15, Thermodynamics

1) During a thermodynamic process 500 J of heat are absorbed and the internal energy decreases by 200 J. The work done is

a) 700 J.

b) 300 J.

c) -700 J.

d) -300 J.

2) During an isothermal process

a) no heat is lost.

b) the temperature is constant.

c) the pressure is constant.

d) the volume must decrease.

3) When the volume of a system increases

a) the temperature also must increase.

b) the entropy decreases.

c) heat flows into the system.

d) the system does work.

4) According to the second law of thermodynamics

a) Heat can never go from a cold body to a hotter one.

b) Heat cannot be converted into work.

c) The efficiency of heat engines is limited by the temperatures between which the engine operates.

d) The natural tendency is for systems to go from disordered states to more highly ordered ones.

5) In thermodynamics the amount of disorder in a system is measured by its

a) energy.

b) entropy.

c) heat.

d) pressure.

6) During one cycle in the operation of an automobile engine, the heat produced by burning the gasoline is 200 J and the heat lost to the exhaust is 150 J. The efficiency is:

a) 25%

b) 50%

c) 57%

d) 75%

e) 100%

7) All processes that occur in a closed system must

a) increase the energy of the system.

b) decrease the energy of the system.

c) increase the entropy of the system.

d) decrease the entropy of the system.

e) leave the energy and entropy of the system unchanged.

Ans: 1-a, 2-b, 3-d, 4-c, 5-b, 6-a, 7-c