Question

2. A 35g ball of brass at 25 0C is placed in a pot of boiling water reading 120 0C until equilibrium is reached. How much thermal energy is absorbed by the ball?[ specific heat of brass = 393.5 J/Kg 0C]

a. 1.3 mJ

b. 1.3 MJ

c. 1.3 kJ

d. 1.3 J

2. A 40-g mass of an unknown material at 90 0C is placed in 250 g of water at an initial temperature of 15.0 0C. The final temperature is observed to be 26.5 0C. What is the specific heat of the substance?[specific heat of water = 4186 J/Kg 0C]

a. 4.378 kJ / Kg 0C

b. 43.78 kJ / Kg 0C

c. 47. 38 kJ / Kg 0C

d. 4.738 kJ / Kg 0C

3. Efficiency of the engine running between 250 K and 20 K

a. 90%

b. 92 %

c. 95%

d. 20%

Answer 1