For the photoelectric effect, the maximum kinetic energy (Ek) of the photoelectrons is plotted against the frequency (v) of the incident photons as shown in figure. The slope of the graph gives
(A)Ratio of Planck's constant to electric charge
(B)Work function of the metal
(C)Charge of electron
(D)Planck's constant✓ Correct
Answer: (D)
Solution
Einstein's photoelectric equation gives
Kmax=hν−ϕ
Plotting Kmax on the y-axis against frequency ν on the x-axis gives a straight line of the form y=mx+c, with slope m=h and intercept −ϕ.
The slope of the graph is Planck's constant.
JEE Main · 2024 · 30 Jan 2024 · Shift 2 · Single correct option