Physics help

Question

If purple light frequency of 10^16 Hz falls on a metal surface with verge energy 1/3 of energy quanta of the purple light.The kinetic energy of the released electron is...X 10^-18J

A.6.6
B.4.4
C.3.3
D.2.2
E.1.1

Answer 1

The kinetic energy of the electron will be equal to 1/3 of the energy of a quantum of the light.

 

According to the Planck–Einstein relation, the energy of the light is hν, where h is Planck's constant and ν is the frequency of the light.  So...

 

E = 6.626 × 10^-34 m² kg / s * (1/3) * 10¹⁶ / s = 2.20 * 10 ^-18 m² kg / s²

 

So assuming the numbers are in Joules, the answer is D, 2.2