Which equation was used by albert einstein to explain the photoelectric effect? [e = energy, h = planck's constant, and v = frequency.] e = h/v e = hv e = v/h e = h - v

What would be the original temperature of a gas that has a volume of 2.0 l and a pressure of 2.0 atm and an unknown temperature that the volume increased to 3.5 l in its pressure decreased to 1.0 atm if the final temperature is measured to be 11°c