Question

( hleft(4 x 10^{6}right)=h v_{0}+2 k E )
( hleft(2 cdot 5 times 10^{6}right)=h v_{0}+k E )
( 2 x[i i)-(i) )
( Aleft(1 times 10^{6}right)=100 )
( therefore ) Htushold freq ( =10^{6} mathrm{hz} )

# 5 If a light with frequency 4 x 1016 Hz emitted photoelectrons with double the kinetic energy as are emitted by the light of frequency 2.5 x 1016 Hz from the same metal surface, then what is the threshold frequency (no) of the metal ?

Solution