# Quantum Theory

## Homework Statement

A certain photoelectric surface has a threshold frequency of 4.62 X 10^14 Hz.
a) What is the photoelectric work function in joules?
b) The surface is illuminated with light that has a frequency of 5.2 X 10^14 Hz. What is the kinetic energy of the electrons ejected from the surface? Answer in joules and electron volts.

## Homework Equations

1 eV = 1.6 X 10^19 J
W = hf

## The Attempt at a Solution

a) 3.06 X 10^-19 J
b) I need help on! I have no idea which equation to use, etc. Thanks!

Hootenanny
Staff Emeritus
Gold Member

## Homework Statement

A certain photoelectric surface has a threshold frequency of 4.62 X 10^14 Hz.
a) What is the photoelectric work function in joules?
b) The surface is illuminated with light that has a frequency of 5.2 X 10^14 Hz. What is the kinetic energy of the electrons ejected from the surface? Answer in joules and electron volts.

## Homework Equations

1 eV = 1.6 X 10^19 J
W = hf

## The Attempt at a Solution

a) 3.06 X 10^-19 J
b) I need help on! I have no idea which equation to use, etc. Thanks!
Welcome to Physics Forums,

You're answer to part (a) is spot on. Now for part (b), what is the definition of the work function?