The threshold frequency of metal is f 0 . When the light of frequency 2 f 0 is incident on the metal plate,…

The threshold frequency of metal is f0. When the light of frequency 2f0 is incident on the metal plate, the maximum velocity of photoelectron is v1. When the frequency of incident radiation is increased to 5f0. the maximum velocity of photoelectrons emitted is v2. The ratio of v1 to v2 is:
  1. v1v2=12
  2. v1v2=18
  3. v1v2=116
  4. v1v2=14

Solution

Maximum kinetic energy is related to the incident frequency f and the threshold frequency f0 as:

Kmax=hf-hf0

When, f=2f0

12mv12=2hf0-hf0=hf0     ...1

When, f=5f0

12mv22=5hf0-hf0=4hf0    ...2

Hence, the ratio, v1v2=12

Asked in: JEE Main 2023 (01 Feb Shift 2)

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