The magnetic field associated with a light wave is given, at the… | JEE Main 2019 (9 Jan, Shift 2)

Q135JEE Main 2019 · 9 JAN · SHIFT 2Difficult

Photoelectric Effect: Einstein's Equation

The magnetic field associated with a light wave is given, at the origin, by B = B0 [sin(3.14 $\times$ 107)ct + sin(6.28 $\times$ 107)ct]. If this light falls on a silver plate having a work function of 4.7 eV, what will be the maximum kinetic energy of the photo electrons?

(Take c = 3 $\times$ 108 ms ${}^{-1}$ , h = 6.6 $\times$ 10 $-$ 34J-s)

Show answer and solution

Answer: (d)

$\omega = 2\pi\nu$ : $\nu_1 = \frac{3.14 \times 10^7 \times 3 \times 10^8}{2\pi} = 1.5 \times 10^{15}$ Hz and $\nu_2 = 3 \times 10^{15}$ Hz.
Maximum KE comes from the higher frequency: $h\nu_2 = 6.6 \times 10^{-34} \times 3 \times 10^{15} = 1.98 \times 10^{-18}$ J $\approx 12.4$ eV.
$K_{max} = 12.4 - 4.7 \approx 7.7$ eV
So the answer is (d) 7.72 eV.

Report a mistake

More questions on Photoelectric Effect: Einstein's Equation

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)
When a metallic surface is illuminated with radiation of wavelength λ, the stopping…NEET 2016 (Phase 1)
A photoelectric surface is illuminated successively by monochromatic light of wavelengths…JEE Main 2016 (10 Apr, Shift 1)
Radiation of wavelength λ, is incident on a photocell. The fastest emitted electron has…JEE Main 2016

Photoelectric Effect: Einstein's Equation question from JEE Main 2019 (9 Jan, Shift 2)

More questions on Photoelectric Effect: Einstein's Equation