In a photodiode,the conductivity increases when the material is exposed to light.It is found that the conductivity changes only if the wavelength is less than 620nm.What is the band gap?

Explanation

To find the band gap of the photodiode material, we can use the relationship between energy, wavelength, and the constants of physics. Here’s a step-by-step solution:

### Step 1: Understand the relationship between energy and wavelength
The energy (E) of a photon can be calculated using the formula:
\[ E = \frac{hc}{\lambda} \]
where:
- \( E \) is the energy in electron volts (eV),
- \( h \) is Planck's constant (\( 4.136 \times 10^{-15} \) eV·s),
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