The light intensity incident on a metallic surface produces photoelectrons with a maximum kinetic energy of 2 eV. if The frequency of the light is doubled. Determine the maximum kinetic energy (in eV).

Modern physics a photon emitted from an excited hydrogen atom has an energy of 3.02 electron volts. which electron energy-level transition would produce this photon? a. n=1 to n=6 b. n=2 to n=6 c. n=6 to n=1 d. n=6 to n=2 i chose b but the correct answer is d can someone tell me why? and what's the difference?