Question

With neat labelled circuit diagram, describe an experiment to study the characteristics of the photoelectric effect.

Hint:

The photoelectric effect demonstrates that light behaves as discrete packets (photons) that can knock electrons off a metal surface when they have sufficient energy.

Answer 1

Step 1: The Experimental Setup.
The experimental setup consists of a light source, a cathode (metal plate), an anode, and a voltmeter to measure the photoelectric current. The light source is used to shine light of different intensities and frequencies on the cathode.
Step 2: Circuit Diagram.
The cathode is connected to a negative terminal of a battery and the anode to the positive terminal. The circuit is shown as follows: \[ \text{[Circuit Diagram: Metal Plate (Cathode)} \rightarrow \text{Light Source} \rightarrow \text{Anode} \rightarrow \text{Voltmeter}] \]
Step 3: Procedure.
1. The cathode is illuminated with light of different frequencies and intensities. 2. The emitted photoelectrons are attracted towards the anode, creating a current. 3. The current is measured using the voltmeter. 4. By varying the frequency and intensity of light, we can observe how the current changes.
Step 4: Results and Conclusion.
The photoelectric current increases with the intensity of light, but it is independent of the frequency of light above a certain threshold frequency. The experiment confirms that light has particle-like properties, and the photoelectric effect cannot be explained by wave theory alone.