Question

What happens when light falls upon a light dependent resistor placed in a circuit?

• A. The current going through the LDR decreases.
• B. The LDR begins to glow.
• C. The voltage across the LDR decreases.
• D. Its resistance decreases.

Answer 1

The correct option is D Its resistance decreases.

Light dependent resistor works on principle of photo conductivity. When light falls i.e. photons fall on this, electrons get energized and occupy conduction band escaping from valance band. These electrons in conduction band increase conductivity and decrease resistivity.