When the light of frequency 2ν _0 (where ν _0 is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is…
NEET UG 2018 — Physics Modern Physics
2018mcqeasy
When the light of frequency 2ν0 (where ν0 is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is v1. When the frequency of the incident radiation is increased to 5ν0, the maximum velocity of electrons emitted from the same plate is v2. The ratio of v1tov2 is
Official previous-year question
Held on 30 Apr 2018 · Verified 9 Jul 2026.
Options
A
4 : 1
B
1 : 4
C
1 : 2
D
2 : 1
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Solution
From Einstein's equation of Photoelectric effect, we can write
For case 1: 21mv12=2hν0−hν0⇒21mv12=hv0 ... (i), where m is mass of electron, h is Planck's constant.
For case 2: 21mv22=5hν0−hν0⇒21mv22=4hν0 ... (ii)
From (1) and (2)
v2v1=41=21.
Hence, the ratio of v1 and v2 is 1:2.
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