A photoelectric material has a work function of 4.0 eV . Determine its threshold wavelength.

Correct answer: C. 310 nm The work function and threshold wavelength λ_0 are related by the equation: = (hc)/(λ_0) Given = 4.0 eV and using the standard value hc 1240 eV , we get: λ_0 = 1240 eV 4.0 eV λ_0 = 310 nm

Concepts Of Physics MCQ Edition [Volume 2]

Exam: Concepts Of Physics MCQ Edition [Volume 2]
Subject: Physics
Chapter: Photoelectric Effect and Wave–Particle Duality

Concepts Of Physics MCQ Edition [Volume 2] · Physics · Photoelectric Effect and Wave–Particle Duality

A photoelectric material has a work function of 4.0 eV . Determine...

A photoelectric material has a work function of

4.0 \text{ eV}

. Determine its threshold wavelength.

Options

A $414 \text{ nm}$
B $155 \text{ nm}$
C $310 \text{ nm}$
D $620 \text{ nm}$

Correct answer

C. $310 \text{ nm}$

Step-by-step solution

The work function

\Phi

and threshold wavelength

\lambda_0

are related by the equation:

\Phi = \dfrac{hc}{\lambda_0}

Given

\Phi = 4.0 \text{ eV}

and using the standard value

hc \approx 1240 \text{ eV}\cdot\text{nm}

, we get:

\lambda_0 = \dfrac{1240 \text{ eV}\cdot\text{nm}}{4.0 \text{ eV}}

\lambda_0 = 310 \text{ nm}

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