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See all →- Two gases A and B are filled at the same pressure in separate cylinders with movable pistons of radius r_A and r_B, respectively. On supplying an equal amount of heat to both the systems reversibly under constant pressure, the pistons of gas A and B… Answer: 2. 3/4 Key idea: at constant pressure, Q=Δ U+W with W=pΔ V . The heat supplied and Δ U are the same for both gases, so W is equal. W... 1
- A thermodynamic system is taken through the cycle abcda. The work done by the gas along the path bc is : Answer: 2. zero Key idea: Work done by a gas is W=∫ P dV , so it is zero when the volume does not change. In the figure, path bc is vertical... 1
- A Carnot engine has an efficiency of 50% when its source is at a temperature 327^° C. The temperature of the sink is : Answer: 2. 27^° C Carnot efficiency: η=1-T₂/T₁ with temperatures in kelvin. T₁=327+273=600 K, η=0.5⇒ T₂=0.5×600=300 K = 27^° C. The answer i... 1
- An ideal gas undergoes four different processes from the same initial state as shown in the figure below. Those processes are adiabatic, isothermal, isobaric and isochoric. The curve which represents the adiabatic process among 1, 2, 3 and 4 is : Answer: 3. 2 On a P-V diagram, all processes start from the same point. Curve 1 is vertical (constant volume, isochoric) and curve 4 is hori... 1
- Two cylinders A and B of equal capacity are connected to each other via a stop cock. A contains an ideal gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stop cock is suddenly opened.… Answer: 2. adiabatic The system is thermally insulated, so no heat enters or leaves: Q=0 . That makes the process adiabatic. (This is a free... 1
- In which of the following processes, heat is neither absorbed nor released by a system ? Answer: 2. adiabatic In an adiabatic process Δ Q=0 by definition: no heat enters or leaves the system. In isothermal, isobaric and isochoric... 1