Lenard observed that when UV-radiations were allowed to fall on the emitter plate of an evacuated glass tube enclosing two electrodes, current flows in the circuit as shown in figure. Reason is

Question

Lenard observed that when UV-radiations were allowed to fall on the emitter plate of an evacuated glass tube enclosing two electrodes, current flows in the circuit as shown in figure. Reason is (A) UV-light ionises the traces of gas left after evacuation (B) UV-light produces ionisation of cathode and anode (C) UV-light causes ionisation of cathode (D) UV-light causes ejection of electrons from the emitter plate

Tardigrade Admin · Accepted Answer

When ultraviolet radiations fall on the emitter plate, electrons are ejected from it which are attracted towards the positive collector plate by the electric field. The electrons flow through the evacuated glass tube, resulting in the current flow.

Q. Lenard observed that when UV-radiations were allowed to fall on the emitter plate of an evacuated glass tube enclosing two electrodes, current flows in the circuit as shown in figure. Reason is

UV-light ionises the traces of gas left after evacuation

UV-light produces ionisation of cathode and anode

UV-light causes ionisation of cathode

UV-light causes ejection of electrons from the emitter plate

When ultraviolet radiations fall on the emitter plate, electrons are ejected from it which are attracted towards the positive collector plate by the electric field. The electrons flow through the evacuated glass tube, resulting in the current flow.