1) Describe two sets of conditions of heat and work that cause an increase in internal energy.

2)  Write one or two sentences describing how a heat engine works.

3) A neatly arranged bookshelf is a very orderly system and has low entropy. Why is it safe to assume that this did not happen naturally? Write one or two sentences explaining your answer.

Answer:

1.

 To increase internal energy

(i) heat must given to system and

(ii) Work is done on system.

2.

Heat engine is the device which convert heat into work. It has three part source (high temperature body), working substance and sink (low temperature body). It takes heat from high temperature source and convert it into work and remaining heat goes to sink.

3.

Naturally ocuuring phenomenon favour randomness( or increasing entropy) e.g. ice (high ordered) melts naturally into water (less order). This is second law of thermodynamics. Hence arrangement of ordered booksheft (Low entroy or less randomness) will not occur naturally.