A refrigerator is to maintain eatables kept inside at `9^(@)C`. If room temperature is `36^(@)C`, calculate the coefficient of performance.

An electric heater is used in a room of total wall area 137m^(2) to maintain a temperature of +20^(@)C inside it when the outside temperature is -10^(@)C . The walls have three different layers materials . The innermost layer is of wood of thickness 2.5 cm, in the middle layer is od cement of thickness 1.0 cm and the outermost layer is of brick of thickness 25.0 cm. find the power of the electric heater. Assume that there is no heat loss through the floor and the ceiling. The thermal conductives of wood, cement and brick are 0.125, 1.5 and 1.0 watt//m// .^(@)C respectively.

Refrigerator is an apparatus which takes heat from a cold body, work is done on it and the work done together with the heat absorbed is rejected to the source. An ideal refrigerator can be regarded as Carnot's ideal heat engine working in the reverse direction. The coefficient of performance of refrigerator is defined as beta = ("Heat extracted from cold reservoir")/("work done on working substance") = (Q_(2))/(W) = (Q_(2))/(Q_(1)- Q_(2)) = (T_(2))/(T_(1) - T_(2)) A Carnot's refrigerator takes heat from water at 0^(@)C and discards it to a room temperature at 27^(@)C . 1 Kg of water at 0^(@)C is to be changed into ice at 0^(@)C. (L_(ice) = 80"kcal//kg") What is the coefficient of performance of the machine?

Refrigerator is an apparatus which takes heat from a cold body, work is done on it and the work done together with the heat absorbed is rejected to the source. An ideal refrigerator can be regarded as Carnot's ideal heat engine working in the reverse direction. The coefficient of performance of refrigerator is defined as beta = ("Heat extracted from cold reservoir")/("work done on working substance") = (Q_(2))/(W) = (Q_(2))/(Q_(1)- Q_(2)) = (T_(2))/(T_(1) - T_(2)) A Carnot's refrigerator takes heat from water at 0^(@)C and discards it to a room temperature at 27^(@)C . 1 Kg of water at 0^(@)C is to be changed into ice at 0^(@)C. (L_(ice) = 80"kcal//kg") How many calories of heat are discarded to the room?

Refrigerator is an apparatus which takes heat from a cold body, work is done on it and the work done together with the heat absorbed is rejected to the source. An ideal refrigerator can be regarded as Carnot's ideal heat engine working in the reverse direction. The coefficient of performance of refrigerator is defined as beta = ("Heat extracted from cold reservoir")/("work done on working substance") = (Q_(2))/(W) = (Q_(2))/(Q_(1)- Q_(2)) = (T_(2))/(T_(1) - T_(2)) A Carnot's refrigerator takes heat from water at 0^(@)C and discards it to a room temperature at 27^(@)C . 1 Kg of water at 0^(@)C is to be changed into ice at 0^(@)C. (L_(ice) = 80"kcal//kg") What is the work done by the refrigerator in this process ( 1 "cal" = 4.2 "joule" )

A clock with a metallic pendulum gains 6 seconds each day when the temperature is 20^(@)C and loses 6 second when the temperature is 40^(@)C . Find the coefficient of linear expansions of the metal.

The temperature inside a refrigerator is t_2^@C and the room temperature is t_1^@C . The amount of heat delivered to the room for each joule of electrical energy consume ideally will be _____

An ice box used for keeping eatables cool has a total wall area of 1m^2 and a wall thichness of 5.0 cm. The thermal cunductivity of the ice box is K=0.01 J//m^@C . It is filled with large amount of ice at 0^@C along with eatables on a dfay when the temperature is 30^@C The latent heat of fusion of ice is 334xx10^3 J//kg . The amount of ice melted in one day is ( 1 day =86,000s )

If the coefficient of performance of a refrigerator is 5 and operates at the room temperature (27^@C) , find the temperature inside the refrigerator.

Area of surface of a person is "1.9 m"^(2) and its body temp. is 37^(@)C and room temp. is 22^(@)C . Temperature of skin is 28^(@)C , then find the rate of emission of heat. Emissivity of skin is 0.97 .

A refrigerator takes heat from water at 0^(@)C and transfer it to room at 27^(@)C . If 100 kg of water is converted in ice at 0^(@)C then calculate the work done. (Latent heat of ice 3.4xx10^(5) J//kg )