Photoelectric Effect

Work function eV = J = J
Using:
Substitute: Js, m/s
m = 258 nm

Using the photoelectric equation: $ E_k h \nu W h = 6.626 \times 10^{-34} \ \text{Js} \nu = \frac{c}{\lambda} = \frac{3 \times 10^{8}}{3000 \times 10^{-10}} = 10^{14} \ \text{Hz} W = 2.13 \ \text{eV} $

Step 1: Apply Einstein’s Photoelectric Equation Step 2: Compute Electron Velocity Thus, the correct answer is .

Let’s break this down step by step to calculate the kinetic energy of the ejected electrons and determine why option (2) is the correct answer.
Step 1: Understand the photoelectric effect
The kinetic energy of the ejected electrons is given by Einstein’s photoelectric equation:

where:

• is the energy of the incident photon,
• is the work function of the material.

Step 2: Calculate the energy of the incident photon
The energy of a photon is:

• Planck’s constant,
• Speed of light,
• Wavelength,

Step 3: Calculate the kinetic energy
Work function, .

This is very close to 1.32 J, likely due to rounding.
Step 4: Confirm the correct answer
The calculated kinetic energy is approximately 1.34 J, which matches option (2) 1.32 J, accounting for slight rounding differences.
Thus, the correct answer is (2) 1.32 .