LED is constructed from |SemiconductorElectroniJEEMain2021

JEE MAIN 2021

26-02-2021 S1

Question

LED is constructed from Ga-As-P semiconducting material. The energy gap of this LED is 1.9 eV. Calculate the wavelength of light emitted and its colour. $\left[\mathrm{h}=6.63 \times 10^{-34} \mathrm{Js}\right.$ and $\left.\mathrm{c}=3 \times 10^8 \mathrm{~ms}^{-1}\right]$

Select the correct option:

1046 nm and red colour

654 nm and orange colour

1046 nm and blue colour

654 nm and red colour

✓ Correct! Well done.

✗ Incorrect. Try again or view the solution.

Solution

$\begin{aligned} & \lambda=\frac{\mathrm{hc}}{\mathrm{E}}=\frac{6.6 \times 10^{-34} \times 3 \times 10^8}{1.9 \times 1.6 \times 10^{-19}}=6.54 \times 10^{-7} \\ & =654 \mathrm{~nm} \\ & \text { Red color }\end{aligned}$

Question Tags

JEE Main

Physics

Easy

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