Question

6. The threshold frequency of a metal corresponds to
the wavelength of x nm. In two separate experiments
A and B, incident radiations of wavelengths 1/2 x nm
and 1/4 x nm respectively are used.
The ratio of kinetic energy of the released electrons
in experiment 'B' to that in experiment 'A' is
(a) 1/3
(c) 4
(e) 1/2
(b) 2
(d) 3
​

Answer 1

In experiment A, incident radiations of 1 wavelength used =21X

In experiment B, incident radiations of wavelength used =41X

 

The ratio of kinetic energy of the released electrons in experiment 'B' to that in experiment 'A':

(KE)A(KE)B=λA1−λ01λB1−λ01[letsλ0=x]

(KE)A(KE)B=x2−x1x4−x1=3