The maximum velocity of electrons emitted from a metal surface is v. What would be the maximum velocity if the frequency of incident lightis increased by a factor of 4?

Options

A. 2v
B. `gt2v`
C. `lt2v`
D. between2v and 4v

Answer

B

Explanation

`(1)/(2)mv^2=hv_phi_0`
`(1)/(2)mv^('2)=4hv-phi_0`
`(v^('2))/(v^2)=(4hv-phi_0)/(hv-phi_0)`
or `(v^('2))/(v^2)=(4[hv-phi]+3phi_0)/(hv-phi_0)`
Clearly, `v'gt2v`