# Waves behave like particles

### Introduction

### Examples

#### Lessons

- The stopping potential, $V_{0}$, that prevents electors from flowing across a certain photocell is 6.0V. What is the kinetic energy given to the electrons by incident light? Give your answer in both $J$ and $eV$. Sketch the problem and calculate your answer.
- Potassium threshold wavelength is 564 nm,
- Find the work function of potassium in $eV$.
- If the ultraviolet radiation with a wavelength of 246 nm falls on potassium, what is the energy of the ejected electrons in $eV$. Sketch the problem and calculate your answer.

- The stopping potential required to prevent current through a photocell is 4.2$V$. Calculate the kinetic energy in joules and in $eV$ of the photoelectrons as they are emitted.
- The threshold wavelength of copper is 264 $nm$.
- Find the threshold frequency of copper.
- What is the work function in $eV$ of copper?
- Copper in a photocell is irritated by ultraviolet light of 140 $nm$ wavelength. What is the kinetic energy of the photoelectrons in $eV$?

- The work function for cadmium is 4.07 $eV$.
- Find the threshold wavelength for cadmium.
- What is the kinetic energy in $eV$ of photoelectrons ejected when 190 nm violet light falls on the cadmium?

- An X ray with a wavelength 6.0 x 10
^{-14}$m$ is travelling in a vacuum.- Calculate the momentum associated with this X ray.
- Why does the X ray exhibit little particle behavior?

- The work function of sodium is 2.28 $eV$.
- What is the threshold wavelength of sodium?
- Sodium is exposed to radiation of wavelength 160$nm$. What is the maximum kinetic energy of the ejected electrons in $eV$?