In an experiment of photoelectric effect the stopping potential was measured to be `V_(1) and V_(2)` with incident light of wavelength `lamda and lamda/2`, respectively. The relation between `V_(1) and V_(2)` is

Options

A. `V_(2) gt 2V_(1)`
B. `V_(2) lt V_(1)`
C. `V_(1) lt V_(2) lt 2V_(1)`
D. `V_(2) = 2V_(1)`

Answer

A

Explanation

`eV = hf - W or, (hc)/(lamda) = eV + W`
For these two case, `(hc)/(lamda) = eV_(1) + W`
and `(hc)/(lamda//2) = eV_(2) + W`
hence, `(2hc)/(lamda) = eV_(2) + W`
`:. eV_(1) + W = 2eV_(1) + 2W`
or, `V_(2) = 2V_(1) + (W)/(e) "so", V_(2) gt 2V_(1)`