when the light of frequency 2ν0 (Where ν0 is threshold frequency ) is incident on a metal plate , the maximum velocity

Q: when the light of frequency 2ν₀ (Where ν₀ is threshold frequency ) is incident on a metal plate , the maximum velocity of electron emitted is v₁ . When the frequency of incident radiation is increased to 5ν₀ , the maximum velocity of electron emitted from the same plate is v₂ . The ratio of v₁ to v₂

(a)4:1

(b)2:1

(c)1:4

(d)1:2

Ans: (d)

Sol: In case (i)

h.2ν₀ = h.ν₀ + (1/2)m v₁²

h.ν₀ = (1/2)m v₁² …(i)

In case (ii)

h.5ν₀ = h.ν₀ + (1/2)m v₂²

h.4ν₀ = (1/2)m v₂² …(ii)

Dividing equations (i) and (ii) we get

v₁/v₂ = 1/2