# In an Experiment on Photoelectric Effect, the Slope of the Cut-off Voltage Versus Frequency of Incident Light is Found to Be 4.12 × 10−15 V S. Calculate the Value of Planck’S Constant. - Physics

In an experiment on the photoelectric effect, the slope of the cut-off voltage versus frequency of incident light is found to be 4.12 × 10−15 Vs. Calculate the value of Planck’s constant.

#### Solution

The slope of the cut-off voltage (V) versus frequency (ν) of an incident light is given as:

V/v = 4.12 xx 10^(-15) Vs

V is related to frequency by the equation:

hv = eV

Where

e = Charge on an electron = 1.6 × 10−19 C

h = Planck’s constant

:. h = e xx V/v

= 1.6 xx 10^(-19) xx 4.12 xx 10^(-15) = 6.592 xx 10^(-34) Js

Therefore, the value of Planck’s constant is 6.592 xx 10^(-34) Js

Concept: Einstein’S Photoelectric Equation: Energy Quantum of Radiation
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#### APPEARS IN

NCERT Class 12 Physics Textbook
Chapter 11 Dual Nature of Radiation and Matter
Q 6 | Page 407