Question

The threshold frequency for a certain photosensitive metal is v₀. When it is illuminated by light of frequency v = 2v₀, the maximum velocity of photoelectrons is v₀. What will be the maximum velocity of the photoelectrons when the same metal is illuminated by light of frequency 

v = 5v₀?

पर्याय

• `sqrt2  "v"_0`

• 2 v₀

• `2 sqrt2  "v"_0`

• 4 v₀

Answer 1

2 v₀

Explanation:

`1/2"mv"_"max"^2 = "h"("v" - "v"_0)`

For light of frequency v = 2 v₀ , we have

`1/2"mv"_0^2 = "h" (2"v"_0 - "v"_0) = "hv"_0`   ....(i)

For light of frequency v = 5 v₀, we have

`1/2"mv'"^2 = "h"(5"v"_0 - "v"_0) = 4"hv"_0`    .....(ii)

Dividing equation (ii) by equation (i), we ge

`"v'"^2 = 4_0^2 or "v'" = 2"v"_0.`