Question

When the work function of a metal increases, maximum kinetic energy of emitted photoelectrons

• A. first decreases and then increases.
• B. increases.
• C. remains same.
• D. decreases.

Hint:

Higher work function means more energy is required to eject electrons, leaving less energy as kinetic energy.

Answer 1

The Correct Option is D

Step 1: Einstein’s photoelectric equation.
\[ K_{\max} = h\nu - \phi \] where $\phi$ is the work function of the metal.

Step 2: Effect of increasing work function.
For a given frequency $\nu$, if $\phi$ increases, the term $(h\nu - \phi)$ decreases.

Step 3: Conclusion.
Hence, the maximum kinetic energy of emitted photoelectrons decreases.