Question

Explain the observations made by Hertz and Lenard about the phenomenon of photoelectric emission.

Answer 1

Hint: When a substance absorbs electromagnetic radiation, electrically charged particles are emitted from or inside it, causing the photoelectric effect. The emission of electrons from a metal frame when light hits on it is a common definition of the effect.

Complete step by step solution:
We can explain the observations made by Hertz and Lenard about the phenomenon of photoelectric emission as,
1. Hertz discovered that high volt charges across the sensor loop were amplified when the emitter plate was lit by UV light from an arc lamp during his experimental inquiry on the creation of electromagnetic waves by spark discharge.

2. When UV light is permitted to fall on the emission plate of an evacuated glass tube containing two metal plates or two electrodes, current flows in the circuit, according to Lenard.

3. The current flow ceased as soon as the UV radiations were turned off. These findings showed that when UV rays strike the emitter plate, electrons are produced, which are then drawn to the positive collection plate by the electric field.

4. The current in the open circuit is created by electrons flowing through the surface of emitters.

5. Lenard and Hallwachs looked at and examined how the photocurrent changed as the collector plate potential, frequency, and intensity of incoming light changed.

So, we explained the observations made by Lenard and Hertz about the phenomenon of photoelectric emission.

Note: While explaining the observations, try to understand which one is the emitter and what will it do, that is, produce electrons for the photoelectric emission.