Target Exam

CUET

Subject

Physics

Chapter

Dual Nature of Radiation and Matter

Question:

The work function of a photoelectric surface is 3.3 eV. The value of the threshold frequency for the surface is:

Options:

$8 \times 10^{14} Hz$

$5 \times 10^{16} Hz$

$4 \times 10^{11} Hz$

$8 \times 10^{10} Hz$

Correct Answer:

$8 \times 10^{14} Hz$

Explanation:

The correct answer is Option (1) → $8 \times 10^{14} Hz$

Given,

ϕ, Work function = 3.3 eV

h, Planck's constant = $4.13×10^{-15}eV$

Now,

$f_0$, minimum frequency of incident light required to eject photoelectrons

$ϕ=h.f_0$

$f_0=\frac{ϕ}{h}=\frac{3.3}{4.1357×10^{-15}}$

$≈8 \times 10^{14} Hz$