A photon of wavelength 0.62395 nm strikes a free electron that is initially at rest. The photon is scattered straight backward. What is the speed of the recoil electron after the collision

A150 w lamp emits light of wavelength 590 nm uniformly in all directions. what is the photon flux (photons per unit area per unit time) on a small screen at a distance 2.3 m from the lamp? assume the photons are uniformly distributed over the surface of a sphere of radius 2.3 m.

Abug is 12 cm from the center of a turntable that is rotating with a frequency of 45 rev/min . what minimum coefficient friction is required so that the bug stays on the turntable?

If 21.2 kcals of energy is released by this reaction, how many kj does the reaction release? (1 cal 4.184 j)