Let P and E denote the linear momentum and energy of emitted photon respectively. If the wavelength of incident radiation is increased, then

Options

A. both p and E increase
B. p increases and E decreases
C. p decreases and E increases
D. both p and E decrease

Answer

D

Explanation

`hv=W_(0)+1/2mv_("max")^(2)`
or `(hc)/(lambda)=W_(0)+1/2 mv_("max")^(2)`
If `lambda` is increased, energy of incident radiation is decreased . The work function remains constant .
`:.1/2 mv^(2)` will decrease and momentum p
`=`mv will decrease
Thus both p and E will decrease.