Title 12.THERMODYNAMICS - Questions.pdf ✅

bucket of water at 50°C (Assume temperature of water does not change) (a.) −4.5 cal/K (b.) +4.5 cal/K (c.) +5.4 cal/K (d.) −5.4 cal/K (38.)The sink temperature of a heat engine 77°C. The efficiency is 30%. The source temperature is (a.) 500°C (b.) 227°C (c.) 317°C (d.) 427°C (39.)Figure shows a thermodynamical process on one moles a gas. How does the work done in the process change with time? (a.) Decrease continuously (b.) Increases continuously (c.) Remains constant (d.) First increase and then decreases (40.)When 1 kg of ice at 0°C melts to water at 0°C, the resulting change in its entropy, taking latent heat of ice to be 80 cal/°C is (a.) 293 cal/K (b.) 273 cal/K (c.) 8 × 104 cal/K (d.) 80 cal/K (41.)A container having 1 mole of a gas at a temperature 27°C has a movable piston which maintains at constant pressure in container of 1 atm. The gas is compressed until temperature becomes 127°C. The work done is (Cpfor gas is 7.03cal/mol − K) (a.) 703 J (b.) 814 J (c.) 121 J (d.) 2035 J (42.)The temperature of a hypothetical gas increases to √2 times when compressed adiabatically to half the volume. Its equation can be written as (a.) PV 3/2 = constant (b.) PV 5/2 = constant (c.) PV 7/3 = constant (d.) PV 4/3 = constant (43.)Three samples of the same gas A, B and C(γ = 3/2) have initially equal volume. Now the volume of each sample is doubled. The process is adiabatic for A isobaric for B and isothermal for C. If the final pressure are equal for all three samples, the ratio of their initial pressures are (a.) 2√2 ∶ 2 ∶ 1 (b.) 2√2 ∶ 1 ∶ 2 (c.) √2 ∶ 1 ∶ 2 (d.) 2 ∶ 1 ∶ √2 (44.)In the cyclic process shown in the figure, the work done by the gas in one cycle is (a.) 28 P1V1 (b.) 14 P1V1 (c.) 18 P1V1 (d.) 9 P1V1 (45.)The change in internal energy, when a gas is cooled from 927°C to 27°C (a.) 300% (b.) 400% (c.) 200% (d.) 100% (46.)dU+dW=0 is valid for (a.) Adiabatic process (b.) Isothermal process (c.) Isobaric process (d.) Isochoric process (47.)An ideal heat engine works between temperatures T1 = 500K and T2 = 375K. If the engine absorbs 600 J of heat from the source, then the amount of heat released to the sink is (a.) 450 J (b.) 600 J (c.) 45 J (d.) 500 J (48.)If heat given to a system is 6 kcal and work done is 6 kJ. Then change in internal energy is (a.) 19.1 kJ (b.) 12.5 kJ (c.) 25 kJ (d.) Zero (49.)The pressure and density of a given mass of a diatomic gas (γ = 7 5 ) change adiabatically from (p, d) to (p’, d’). If d′ d = 32, then P′ p is (γ = ratio of specific heats) (a.) 1/128 (b.) 1/64 (c.) 64 (d.) 128 V1 4V1 P1 7P1 P V