When you exercise in the morning, by considering your body as thermodynamic system, which of the following is true?

(a)

ΔU > 0, W > 0,

(b)

ΔU < 0, W > 0,

(c)

ΔU < 0, W < 0,

(d)

ΔU = 0, W > 0,

An ideal gas is taken from (P_i, V_i) to (P_f, V_f) in three different ways. Identify the process in which the work done on the gas the most.

(a)

Process A

(b)

Process B

(c)

Process C

(d)

Equal work is done in Process A, B & C

A distant star emits radiation with maximum intensity at 350 nm. The temperature of the star is

(a)

8280 K

(b)

5000 K

(c)

7260 K

(d)

9044 K

In an isochoric process, we have

(a)

W = 0

(b)

Q = 0

(c)

ΔU = 0

(d)

ΔT = 0

An ideal refrigerator has a freezer at temperature −12°C. The coefficient of performance of the engine is 5. The temperature of the air (to which the heat ejected) is

(a)

50°C

(b)

45.2°C

(c)

40.2°C

(d)

37.5°C