A Carnot engine has an efficiency of 20 When temperature of sink is reduced by 80 C its efficiency is doubled The temperature of source is NCERT Pg 313 me 1 1492 C 2 400 C 3 127 C 4 80 C In the adiabatic expansion of an ideal gas select the incorrect statement NCERT Pg 312 1 There is decrease in temperature of the gas 2 There is decrease in internal energy of the gas 3 The work done is positive 4 The work done by gas is equal to heat supplied An ideal gas has initial volume V and pressure P To triple its volume the minimum work done will be in 1 Isothermal process 2 Adiabatic process 3 Isobaric process 4 Equal in all process An ideal gas of adiabatic exponent is expanding at constant pressure The ratio of dQdU dW is Symbols have their usual meanings NCERT Pg 309 1 7 5 1 2 7 2 5 3 2 1 1 4 7 5 2 12 A refrigerator is to maintain etables kept inside at 2 C If room temperature is 27 C then coefficient of performance of refrigerator is NCERT Pg 322 1 10 2 9 3 11 4 8 1 The given figure shows the pressure temperature P T diagram for a fixed mass of an ideal gas undergoing cyclic process ABCA The corresponding pressure volume P V graph 3 NCERT Pg 312 14 Which of the following is incorrect NCERT Pg 305 1 If two systems A and B are in thermal equilibrium with system C separately then A and B will be in thermal equilibrium 2 Zeroth law of thermodynamics defines temperature 3 Temperature does not determine the direction of flow of heat when two bodies are placed in thermal contact 1 4 Internal energy of an ideal gas depends on the state of the system 3 2 15 Which of the following graph does not belong to isothermal process for an ideal gas NCERT Pg 311 P 4 P P V P B PV constant V V 2 4 P O V A B F