During an adiabatic process an object does 100 J of work and its temperature decreases by 5K. During another process it does 25 J of work and its temperature decreases by 5K. Its heat capacity for 2nd process is:. a. 20J/K
b. 24J/K
c. 15J/K
d. 100/K

(C) the heat capacity for 2nd process is 15 J/K.

Explanation:

Given;

work, W = 100 J

change in temperature, = -5 K

For the first process;

dQ = dU + dW

for adiabatic process, dQ = 0

0 = dU + dW

dU = - dW

dU = -100 (This remains the same for the second process).

For the second process;

Let C be the heat capacity for 2nd process.

C (dT) = dU' + dW'

dU' = dU = -100

W' = 25

dT = -5 (decrease in temperature)

C(-5) = -100 + 25

-5C = -75

C = -75 / -5

C = 15 J/K.

Therefore, the heat capacity for 2nd process is 15 J/K.

d. air pressure decreases as altitude increases.

b.a device that inputs heat into a cool object