Related InterviewSolutions

• Find the efficiency of a cycle consisting of two isochoric and two adiabatic lines if the volume of the ideal gas changes `n=10` times within the cycle. The working gas has `gamma=1.5`.
• In a mechanical refrigerator the low -temperature coils are at a temperature of `-13^(@)C` and the compressed gas in the condenser at a temperature `27^(@)C`. What is the theoretical coefficient of performance.
• In a two stage heat engine a quantity of heat `Q_(1)` is absorbed at a temperature `T` work `W_(1)` is done and a quantity of heat `Q_(2)` expelled at a lower temperature `T_(2)` by the first state. The second state absorbs the heat expelld by the first, does work `W_(2)` and expels a quanity of heat `Q_(3)` at a lower temperature `T_(2)` Calculate the effiency of the combination engine.
• A brass rod is in thermal contact with a heat reservoir at `127^(@)C` at one end and a heat reservoir at `27^(@)C` at the other end. Find the total change in entropy arising from the process of conduction of 1200 cal of heat through the rod. Does the entropy of the rod change?
• In a specific heat experiment `100g` of lead (sp. Heat`=145Jkg^(-1)K^(-1)`) at `100^(@)C` is mixed with `200g` of water at `20^(@)`. Find the change in entropy.
• Calculate the efficiency of a cycle consisting of two isobaric and two adiabtic lines, if the pressure changes `n=10` times within the cycle. The working substances is an ideal gas of adiabatic exponent `gamma=1.5`.
• The heat capacity of a refrigerating chamber is `80000cal`. Calculate the time in which the temperature of the chamber is reduced from `0.5^(@)C` ot `0^(@)C` if the power of the motor working the machine is `300W`. Ambient temperature `=27^(@)C`.
• The entropy of `v = 4.0` moles of an ideal gas increases by `Delta S = 23 J//K` due to the isothermal expansion. How many times should the volume `v = 4.0` moles of the gas be increased ?