Heat Problems - Physics 12th - Chapter 11 - Sindh Textbook Board (stb problems). Physics class 12 chapter heat problems solution

 

HEAT

(PROBLEMS)

Problem 11.1. i) The normal body temperature is 98.4 F. What is this temperature on Celsius scale? ii) At what temperature do the Fahrenheit and Celsius scales coincide.

Problem 11.2. A steel rod has a length of exactly 0.2cm at 30°C. What will be Its length at 60°C?

Problem 11.3. Find the change In volume of an aluminum sphere of 0.4m radius when It is heated from 0 to 100°C.

Problem 11.4. Calculate the root mean square speed of hydrogen molecule at 800K.

Problem 11.5. a) Determine the average value of the kinetic energy of the particles of an ideal gas at 0°C and at 50°C: b) What is the kinetic energy per mole of an ideal gas at these temperatures?

Problem 11.6. A 2kg iron block is taken from a furnace where its temperature was 650°C and placed on a large block of ice at 0°C. Assuming that all the heat given up by the iron is used to melt the ice, how much ice is melted.

Problem 11.7. In a certain process 400 J of heat are supplied to a system and at the sametime 150J of work are done by the system. What Is the increase in the internal energy of the system.

Problem 11.8. There is an increase of internal energy by 400 joules when 800 joules of work is done by a system. What is the amount of heat supplied during this process?

Problem 11.9. A heat engine performs 200J of work in each cycle and has efficiency of 20 percent. For each cycle of operation a) How much heat is absorbed and b) How much heat is expelled?

Problem 11.10. A heat engine operates between two reservoirs at temperatures of 25°C and 300°C. What is the maximum efficiency for this engine?

Problem 11.11. The low temperature reservoir of a Carnot engine is at 7°C and has an efficiency of 40%. It is desired to increase the efficiency to 50%. By how much degrees the temperature of hot reservoir be increased.