If the current is reduced from 150 a to zero in 0125

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Unformatted text preview: rrent is reduced from 1.50 A to zero in 0.125 s (at a constant rate), what voltage would be measured between the ends A and B of the short coil ( B By Faraday’s Law, the emf generated in the short coil is where turns, 1.50 A / s A/s, and cm is the radius of the solenoid, since there is no field outside its coils. Then 42 turns A Lenz’s Law says that he emf must be directed to generate a current in the same direction that the solenoid’s current had been going, so and 7 7. [9pt] Answer the following multiple choice questions. You do not need to justify your answers, but can get partial credit if you show your work. (a) [3pt] How much work is done per cycle by a gas following the path ABCA shown on the diagram? (A) B J (B) J (C) J A (D) (E) C J J This is the area inside the triangle. (b) [3pt] An ideal gas may expand from an initial pressure and volume to a final volume in a variety of ways. In which of the following processes is the heat added to the gas the largest? (A) Isothermal (B) Adiabatic (C) Isobaric (D) It’s the same in all of these. No heat is added in the adiabatic process: . The heat added in the isothermal process is equal to the work done, The heat added in the isobaric process is where since the temperature increases. The work in this case is Since the pressure decreases in an isothermal expansion, Therefore, (c) [3pt] A heat engine is operated between thermal reservoirs at temperatures of 1600 K and 400 K. What is the minimum amount of power that must be put into the engine to run it if the power output of the engine is 120 kW, according to the laws of thermodynamics? (A) 90 kW (B) 120 kW (C) 160 kW (D) 240 kW The optimal efficiency is that of the Carnot Cycle, so this gives the minimum (E) 480 kW : 8 8. [9pt] Answer the following...
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