Question

A graph is plotted between K.E
of photo electrons (y-axis)
versus frequency of incident
radiation (x-axis). Ratio of
magnitude of y-intercept to
slope will be
(A) Threshold frequency
(B) Threshold wavelength
(C)
1
threshold frequency
(D) Threshold energy​

Answer 1

Answer:

According to Einstein's equation,

hν=W+K.E

max

K.E.

max

=hν−W

Comparing it with equation of straight line with slope m and intercept c,

y=mx+c

We see that on taking K.E

max

on y−axis and frequency of incident radiation on x−axis , we get a straight line with intercept W=workfunction and slope h=Planck’s constant

We see that while plotting the graph of K.E. vs ν for 3 different metals , slope will be same as h is same for all 3 metals. But W is different for different metals . So intercept will be different for different metals