Threshold frequency for metal surface is `4xx10^(14)` Hz.When radiation of `5xx10^(14)`Hz is incident on this surface ,photo-electric current obtained is 1.8 mA.If frequency of incident radiation is made half and intensity is made three times,value of photo-electric current will be.....

Options

A. 0.9 mA
B. 5.4 mA
C. 3.6 mA
D. zero

Answer

D

Explanation

Here threshold frequency,
`V_(0)=4xx10^(14)Hz`
Initially v=`5xx10^(14)`Hz
Now frequency of incident radaition Is made half,
`v.=(5xx10^(14))/(2)=2.5xx10^(14)`Hz
For photo-electric effect v.`gtV_(0)` but here v.`ltV_(0)` hence photo-electric effect will not be obtained .Hence ,current will not be obtained .