Physics-DPP-1-4.First Law of Thermodynamics, Calorimetry and Heat Transfer

PHYSICS Topic: First Law of Thermodynamics, Calorimetry and Heat Transfer Date: 1. An ideal heat engine in operating between 2270C and 1270C. It absorbs 104 J amount of heat at the higher temperature. The amount of heat converted into work is : (a) 2000 J (b) 4000 J (c) 8000 J (d) 5600 J 2. A Carnot engine, with its cold body at 170C has 50% efficiency. If the temperature of its hot body is now increased by 1450C, the efficiency becomes : (a) 55% (b) 60% (c) 40% (d) 45% 3. Two identical containers joined by a small pipe initially contain the same gas at pressure P0 and absolute temperature T0. One container is now maintained at the same temperature, while the other is heated to 2T0. The common pressure of the gases will be : (a) 3 P (b) 4 P (c) 5 P (d) 2P 2 0 3 0 3 0 0 4. During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its absolute temperature. The ratio CP = γ CV for the gas is : 3 5 4 (a) 2 (b) 2 (c) 3 (d) 3 5. A certain amount of an ideal gas is taken from state A to state B, one time by process I and another time by process II. If the amount of heat absorbed by the gas are Q1 and Q2 respectively, then : (a) Q1 = Q2 (b) Q1 < Q2 (c) Q1 > Q2 (d) data insufficient 6. Starting with the same initial conditions, an ideal gas expands from volume V1 to V2 in three different ways. The work done by the gas is W1 if the process is isothermal, W2 if isobaric and W3 if adiabatic, then : (a) W2 > W1 > W3 (b) W2 > W3 > W1 (c) W1 > W2 > W3 (d) W1 > W3 > W2 7. Two different ideal diatomic gaes A and B are initially in the same state. A and B are then expanded to same final volume through adiabatic and isothermal process respectively. If PA, PB and TA, TB represents the final pressure and temperatures at A and B, respectively, then : (a) PA < PB and TA < TB (b) PA > PB and TA > TB (c) PA > PB and TA < TB (d) PA < PB and TA > TB 8. Identify the incorrect statement related to a cyclic process : (a) The initial and final conditions always coincide (b) Q = W (c) W > Q (d) None of the above 9. An ideal gas mixture filled inside a ballon expands according to the relation PV2/3 = constant. The temperature inside the ballon is : (a) increasing (b) decreasing (c) constant (d) cannot be defined 10. A cylindrical tube of uniform cross-sectional area A is fitted with two air tight frictionless pistons. The pistons are connected to each other by a metallic wire. Initially the pressure of the gas is P0 and temperature is T0, atmospheric pressure is also P0. Now, the temperature of the gas is increased to 2T0, the tension in the wire will be : (a) 2P0A (b) P0A P0 A (c) (d) 4P A 2 0 PHYSICS Topic: First Law of Thermodynamics, Calorimetry and Heat Transfer Date: Answer Key 1. (a) 2. (b) 3. (b) 4. (b) 5. (c) 6. (a) 7. (a) 8. (c) 9. (a) 10. (b)

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