Photoelectric emission is observed from a surface for frequencies `v_1` and `v_2` of the incident radiation (`v_1 gt v_2`) if maximum kinetic energies of the photo electrons in the two cases are in the ratio 1:K, then the threshold frequency is given by :

Options

A. `(v_(2)-v_(1))/(K-1)`
B. `(Kv_(2)-v_(1))/(K-1)`
C. `(Kv_(2)-v_(1))/K`
D. `(Kv_(1)-v_(2))/(K-1)`

Answer

4

Explanation

`(E_(1))/(E_(2))=(hv_(1)-phi)/(hv_(2)-phi)=1/K`
`phi=(h(Kv_(1)-v_(2)))/(K-1)=hv`
`v=(Kv_(1)-v_(2))/(K-1)`