Answer the following questions:

a) In order to eject electrons with 11.4 eV of kinetic energy from a metal whose work function is 8.5 eV, what wavelength of light is needed ?

b) Calculate the wavelength of an electron if it has a kinetic energy of 540 eV.

c) What is the kinetic energy of an proton moving at 0.980 c ?

d) Calculate the velocity that will decrease the length of a spaceship by 30%.

e) Planet X is 25.0 light years from earth. How long will it take to travel to planet X at 0.975 c as measured by the captain of the spacecraft ?