Photons of energy 10 eV are incident on a photosensitive surface of threshold frequency 2 × 10¹⁵ Hz. The kinetic energy in eV of the photoelectrons emitted is [Planck's constant h = 6.63 × 10⁻³⁴ Js ] (a) 8.29 eV (b) 6.5 eV (c) 4.2 eV (d) 1.71 eV

Answer: (d). φ = hν₀ = 6.63 × 10⁻³⁴ × 2 × 10¹⁵ = 1.326 × 10⁻¹⁸ J φ = 1.326 × 10⁻¹⁸1.6 × 10⁻¹⁹ = 8.29 eV K = 10 - 8.29 = 1.71 eV So the answer is (d) 1.71 eV.

Photons of energy 10 eV are incident on a photosensitive surface of… | MHT CET 2021 (22 Sep, Shift 2)

Q105MHT CET 2021 · 22 SEP · SHIFT 2Medium

Photoelectric Effect: Einstein's Equation

Photons of energy $10\text{ eV}$ are incident on a photosensitive surface of threshold frequency $2 \times 10^{15}\text{ Hz}$ . The kinetic energy in $\text{eV}$ of the photoelectrons emitted is

[Planck's constant $h = 6.63 \times 10^{-34}\text{ Js}$ ]

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Answer: (d)

$\phi = h\nu_0 = 6.63 \times 10^{-34} \times 2 \times 10^{15} = 1.326 \times 10^{-18}$ J
$\phi = \frac{1.326 \times 10^{-18}}{1.6 \times 10^{-19}} = 8.29$ eV
$K = 10 - 8.29 = 1.71$ eV
So the answer is (d) 1.71 eV.

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Photoelectric Effect: Einstein's Equation question from MHT CET 2021 (22 Sep, Shift 2)

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