Student Login

Home›Chapters›Dual Nature of Radiation and Matter PYQs›Photoelectric Effect: Einstein's Equation›Question 132

MHT CET 2019 (3 May, Shift 1) · Photoelectric Effect: Einstein's Equation

Photoelectric Effect: Einstein's Equation question from MHT CET 2019 (3 May, Shift 1)

Q132MHT CET 2019 · 3 MAY · SHIFT 1Medium

Photoelectric Effect: Einstein's Equation

When certain metal surface is illuminated with a light of wavelength $\lambda$ , the stopping potential is $V$ , When the same surface is illuminated by light of wavelength $2\lambda$ , the stopping potential is $\left(\frac{V}{3}\right)$ . The threshold wavelength for the surface is

Show answer and solution

Answer: (c)

Einstein: $\frac{hc}{\lambda} = \phi + eV_s$ ; write $A = \frac{hc}{\lambda}$ .
$A - \phi = eV$ and $\frac{A}{2} - \phi = \frac{eV}{3}$
$A - \phi = \frac{3A}{2} - 3\phi \Rightarrow \phi = \frac{A}{4}$
$\lambda_0 = 4\lambda$
So the answer is (c) $4\lambda$ .

Report a mistake

More questions on Photoelectric Effect: Einstein's Equation

When a certain photosensitive surface is illuminated with monochromatic light of…JEE Main 2019 (12 Jan, Shift 2)
In a photoelectric experiment, the wavelength of the light incident on a metal is changed…JEE Main 2019 (11 Jan, Shift 2)
The magnetic field associated with a light wave is given, at the origin, by B = B0…JEE Main 2019 (9 Jan, Shift 2)
Surface of certain metal is first illuminated with light of wavelength λ 1 = 350 nm and…JEE Main 2019 (9 Jan, Shift 1)
When the light of frequency 2 v₀ (where v₀ is threshold frequency), is incident on a…NEET 2018
The photoelectric threshold wavelength of silver is 3250 × 10 - 10 m. The velocity of the…NEET 2017 ((one Or More Correct))
The maximum velocity of the photoelectrons emitted from the surface is v when light of…JEE Main 2017 (8 Apr, Shift 1)
Photons with energy 5 eV are incident on a cathode C in a photoelectric cell. The maximum…NEET 2016 (Phase 2)