Question

if the photo of frequency v are incident on the surface of metal A and B of Threshold frequency v/ 2 and v/3 respectively the ratio of maximum Kinetic of electron emitted by a that from B is

Answer 1

If the photo of frequency v is incident on the surface of metal A and B of threshold frequency v/ 2 and v/3 respectively, the ratio of maximum kinetic energy of electron emitted by A to that from B is 3/4 = 0.75.

1. Let the incident radiation on each surface be hv.

2. The threshold radiation of plate A is hv/2.

3. The threshold radiation of plate B is hv/3.

4. Kinetic energy = incident energy - threshold energy.

5. Kinetic energy of plate A is hv - hv/2 =hv/2.

6. Kinetic energy of plate B is hv - hv/3 = 2hv/3.

7. Ratio of kinetic energies of A to B is (hv/2)/(2hv/3) = 3/4.