Question

When $5\times {10}^{11}$ photons each with a wavelength of 0.85 $\mu m$ are incident on a photodiode, on average $2.5\times {10}^{11}$ electrons are collected at the terminals of the device. Then the quantum efficiency of the photodiode is

• A. 0.5%
• B. 5%
• C. 50%
• D. 0.05%

Answer 1

The correct option is C 50%

$\text{Quantum efficiency}=\frac{\text{Number of electrons collected}}{\text{Number of incident photons}}\times 100$

$=\frac{2.5\times {10}^{11}}{5\times {10}^{11}}\times 100=50\%$