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JEE Main 202127 AugustEvening Shift

Exam: JEE Main
Year: 2021
Date: 27 August
Shift: Evening Shift
Subject: Physics
Chapter: Dual Nature of Matter

JEE Main 2021 · 27 August · Evening Shift · Physics · Dual Nature of Matter

A monochromatic neon lamp with wavelength of 670 . 5nm illuminates...

A monochromatic neon lamp with wavelength of

670 . 5nm

illuminates a photo-sensitive material which has a stopping voltage of

0 . 48V

. What will be the stopping voltage if the source light is changed with another source of wavelength of

474 . 6nm

?

Options

A $0 . 24V$
B $1 . 5V$
C $1 . 25V$
D $0 . 96V$

Correct answer

C. $1 . 25V$

Step-by-step solution

${eV}_{s} = \dfrac{hc}{\lambda} - ϕ$

$e\left({V}^{'} - V\right) = hc\left(\dfrac{1}{{\lambda}^{'}} - \dfrac{1}{\lambda}\right)$

${V}^{'} = \dfrac{hc}{e}\left(\dfrac{1}{{\lambda}^{'}} - \dfrac{1}{\lambda}\right) + V$

$= 1240\left(\dfrac{1}{474} - \dfrac{1}{670}\right) + 0 . 48 = 1 . 25eV$

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