Question
Physics Question on Dual nature of radiation and matter
In an experiment on photoelectric effect,the slope of the cut-off voltage versus frequency of incident light is found to be 4.12×10–15Vs. Calculate the value of Planck’s constant.
Answer
The correct answer is: 6.592×10−34Js.
The slope of the cut-off voltage(V) versus frequency(ν) of an incident light is given as:
vV=4.12×10−15Vs
V is related to frequency by the equation:
hv=eV
Where,
e=Charge on an electron=1.6×10−19C
h=Planck's constant
∴h=e×vV
=1.6×10−19×4.12×10−15=6.592×10−34Js
Therefore,the value of Planck’s constant is 6.592×10−34Js.