Lenard's experiment

In this activity you will use the PhET simulation to models Lenard’s experiment.

The first observation of photoelectric effect was by accident when Hertz noticed that if he shone UV light on his radio wave apparatus, the spark was brighter. A brighter spark suggested extra electricity.

15 yrs after this initial observation Lenard started investigating the phenomenon methodically. He set up an experiment to measure current produced when light is shone on metal. He used an evacuated tube with a metal plate at each end. He had an a battery and an ammeter to measure the current produced

Looking at the diagram, why will there be a current?

He wanted to answer the following questions.

How does the intensity of light affect the flow of current?

What would happen if the potential difference at the collection plate is changed?

How does the colour (frequency) effect the the flow of current and stopping voltage?

Is the effect the same for different metals?

We will use the PhET app to gather results to investigate these questions.