(adsbygoogle = window.adsbygoogle || []).push({}); Physics Questions (mult choice!!)

These questions confuse me:

1. A heat engine operates in a Carnot cycle b/w two reservoirs, a hot reservoir at temperature T(h) and a cold reservoir at T(c). The efficiency of the engine is 50%. The temperature of the hot reservoir is increased to 2T(h). The efficiency of the engine now is--- a. 25% b. 33% c. 75% and d. 100%. (If you know of at least an equation I could use, it would be great. I ruled out 100% since it's not really possible, but I really don;t know)

2. Line X has a potential of +50V and line Y has a potential of +100V. The distance between X and Y is 2.0 cm. Which of the following gives the direction of the electric field and its strength? a. X to Y, 25 V/cm b. X to Y, 100 c. Y to X, 25 d. Y to X 100. (I have no idea how to approach this.)

3. The de Broglie wavelength of a particle that has kinetic energy E(k) is lamda. The wavelength lamda is proportial to: a. E(k) b. 1/E(k) c. 1/ square root of E(k) d. E(k)^2. (I said E(k) because they said that E(k) was lamda, but I don't know)

Thanks!!

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Physics Questions (mult choice )

**Physics Forums | Science Articles, Homework Help, Discussion**