A certain when irradiated to light `(v = 3.2 xx 10^(16) Hz)` emit photoelectrons with twice kinetic energy as did photoelectrons when the same metal is irradiation by light `( n = 2.0 xx 10^(16)Hz)` The `v_(0)` Threshold frequency ) of the metal is

Options

A. `12 xx 10^(14) Hz`
B. `8 xx 10^(15) Hz`
C. `1.2 xx 10^(16) Hz`
D. `4 xx 10^(12) Hz`

Answer

D

Explanation

`KE = hv_(0) - hv_(0)`
`hv_(1) - hv_(0)= 2(hv_(2) - hv_(0))`
`v_(0) = 2(v_(2) - v_(1))`
`= 2(2.0 xx 10^(-16)) - (3.2 xx 10^(16))`
`= 8 xx 10^(15) s^(-1) = 8 xx 10^(-15) Hz`