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Physics - Modern Physics Question with Solution | TestHub

PhysicsModern PhysicsPhotoelectric effectEasy2 minPYQ_2020

PhysicsEasysingle choice

When a piece of metal is illuminated by a monochromatic light of wavelength $λ,$ then stopping potential is $3 V_{s} .$ When the same surface is illuminated by the light of wavelength $2 λ,$ then stopping potential becomes $V_{s} .$ The value of threshold wavelength for photoelectric emission will be

Options:

Answer:

Solution:

According to Einstein's photoelectric equation $e V = h c [\frac{1}{λ} - \frac{1}{λ_{0}}]$

Case I: $3 e V_{s} = h c [\frac{1}{λ} - \frac{1}{λ_{0}}]$ ...(i)

Case II: $e V_{s} = h c [\frac{1}{2 λ} - \frac{1}{λ_{0}}]$ ... (ii)

From the Eqs.(i) and (ii), we get

$λ_{0} = 4 λ$

Stream:NTA_ABHYAS_NEETSubject:PhysicsTopic:Modern PhysicsSubtopic:Photoelectric effect

⏱ 2mℹ️ Source: PYQ_2020

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