Change in enthalpy of a system is the heat supplied at___________________?
(A) constant pressure
(B) constant temperature
(C) constant volume
(D) constant entropy
(D) N.T.P. condition
Choose the wrong statement ?
(A) Temperature of medium being cooled must be below that of the evaporator
(B) Refrigerant leaves the condenser as liquid
(C) All solar thermally operated absorption systems are capable only of intermittent operation
(D) frost on evaporator reduces heat transfer
(D) refrigerant is circulated in a refrigeration system to transfer heat
Which one of the following statements is not correct_________________?
(A) the tangent of the angle of friction is equal to coefficient of friction
(B) the angle of repose is equal to angle of friction
(C) the tangent of the angle of repose is equal to coefficient of friction
(D) the sine of the angle of repose is equal to coefficient to friction
(D) none of the above
If value of n is infinitely large in a polytropic process pV” = C, then the process is known as constant_____________________?
(A) volume
(B) pressure
(C) temperature
(D) enthalpy
(D) entropy
A perfect gas at 27°C is heated at constant pressure till its volume is double. The final temperature is________________?
(A) 54°C
(B) 327°C
(C) 108°C
(D) 654°C
(D) 600°C
The value of n = 1 in the poly tropic process indicates it to be __________________?
(A) reversible process
(B) isothermal process
(C) adiabatic process
(D) irreversible process
(D) free expansion process
In order that a cycle be reversible, following must be satisfied ________________?
(A) free expansion or friction resisted expansion/compression process should not be encountered
(B) when heat is being absorbed, temperature of hot source and working sub¬stance should be same
(C) when beat is being rejected, temperature of cold source and working sub-stance should be same
(D) all of the above
(D) none of the above
Which of the following processes are thermodynamically reversible___________________?
(A) throttling
(B) free expansion
(C) constant volume and constant pressure
(D) hyperbolic and pV = C
(D) isothermal and adiabatic
The specific heat of air increases with increase in __________________?
(A) temperature
(B) pressure
(C) both pressure and temperature
(D) variation of its constituents
(D) air flow
The value of the product of molecular weight and the gas characteristic constant for all the gases in S.I. units is________________?
(A) 29.27 J/kmol°K
(B) 83.14J/kmol°K
(C) 848J/kmol°K
(D) All J/kmol °K
(D) 735 J/kmol °K