Question about PHOTOELLECTRIC EFFECT.?
The given is the graph of - frequency of light incident on a metal plate vs kinetic energy of emitted electron.
i. What is the threshold frequency?
ii. If light of 1000Å wavelength is incident on the plate, will electron be emitted?
- RealProLv 76 months ago
E_k = h*f - W
So the slope of the line is h and we are looking for the f-intercept f0.
Using the pair E_k = 5×10^15 and f = 1.2 * 1.6×10^-19 J
Definition of slope
h = (E_k - 0) / (f - f0)
f0 = f - (E_k / h) =
= 2.1×10^15 Hz
1000 Å is frequency of 3×10^15 Hz which is more than f0 so it is enough energy per photon to trigger the effect.