Practicing Success

Target Exam

CUET

Subject

Physics

Chapter

Semiconductors and Electronic Devices

Question:

A photodiode is fabricated with band gap of 3 eV. It can detect

Options:

Visible light

Microwave

Infrared radiation

X-rays

Correct Answer:

Visible light

Explanation:

The correct answer is Option (1) → Visible light

For detection of light by photodiode $E \leq \frac{h c}{\lambda}$

$3 \mathrm{eV} \leq \frac{12400}{\lambda}$

$\lambda \leq \frac{12400}{3} \Rightarrow \lambda \leq 4130 Å$

The photodiode can detect the light lying in visible region (partially) and of ultraviolet region.