1. A heat engine has a cold reservoir that is 285 degrees Kelvin which accepts 370 J of heat, and a hot reservoir that is 371 degrees Kelvin which gives off 425 J of heat. Calculate the maximum and actual efficiencies of this engine. 2. A system that has a total change in entropy of 675 J/K and has received 243 J of heat energy will be at what temperature?

3. Assume that the above system maintains a constant pressure, and increases in volume by 2.5 m 3 while doing this work. What is the pressure of the system?

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.