(a) What is the best coefficient of performance for a refrigerator that cools an environment at -30.0C and has heat transfer to another environment at 45.0C? (b) How much work in joules must be done for a heat transfer of 4186 kJ from the cold environment? (c) What is the cost of doing this if the work costs 10.0 cents per 3.60 X 106 J (a kilowatt-hour)? (d) How many kJ of heat transfer occurs into the warm environment? (e) Discuss what type of refrigerator might operate between these temperatures.

Air is compressed in an adiabatic compressor reversibly from 60.0 kPa and 20°C to 750 kPa. What percentage of work input is transferred to the air as thermal energy or heat? (Round the final answer to three decimal places.) 0% of work input is transferred to the air as thermal energy or heat.

In performing 154.0 J of work, an engine exhausts 65.0 J of heat. What is the efficiency of the engine? e = 29

How much heat transfer (in J) occurs from a system if its internal energy decreased by 290 J while it was doing 43.0 J of work? (Enter the magnitude.)

The rate of heat leaking into a house from the warmer outdoors is given by A(TH – TC) where TC and TH denote the indoor and outdoor temperatures, respectively, and A is a constant.  If the outdoor temperature is 36°C, what will be the ratio of the power required to maintain an indoor temperature of 21°C to that required to maintain an indoor temperature of 25°. Assume the air conditioning system operates at its maximum possible coefficient of performance.

4. A typical coal-fired power plant operates with a high-temperature reservoir at Th = 800 K and a low-temperature reservoir at Tc = 300 K. What is the maximum efficiency allowed by the 2nd law of thermodynamics (the Carnot efficiency) for a heat engine operating between these temperatures?  Give your answer as a decimal number, not as a percentage. (This isn't in section 4.2, so you might want to also take a quick look at equation 4.5 in section 4.5 of the textbook, or at the introductory material in this week's lab write-up.)

Consider the change in the internal energy of a system. -What is the change in the internal energy, in joules, of a system that does 4.725 × 105 J of work, while 3.2 × 106 J of heat is transferred into the system and 7.8 × 106 J of heat is transferred from the system to the environment?

5. (a) How much heat transfer occurs to the environment by an electrical power station that uses1.25 × 10^14 J of heat transfer into the engine with an efficiency of 42.0%? (b) What is the ratioof heat transfer to the environment to work output? (c) How much work is done?

A household refrigerator is .maintained at a temperature of 2°C. Every time the door is opened, warm material is placed inside introducing an average of 420 kJ, but making only a small change in the temperature of the refrigerator. The door is opened 20 times a day and the refrigerator operates at 15% of the Ideal COP. The cost of the work is 4 rupees per kWh. What is the monthly bill for this refrigerator? The atmosphere is at 30°C.

The rate of heat leaking into a house from the warmer outdoors is given by A(TH – TC) where TC and TH denote the indoor and outdoor temperatures, respectively, and A is a constant. If the outdoor temperature is 32°C, what will be the ratio of the power required to maintain an indoor temperature of 21°C to that required to maintain an indoor temperature of 25°. Assume the air conditioning system operates at its maximum possible coefficient of performance.