An LED is constructed from a p-n junction diode using GaAsP. The energy gap is 1.9 eV. The wavelength of the light emitted will be equal to

Question

Question

Answer 1

CONCEPT:

The wavelength is written as;

\(λ = \frac{hc}{E_g}\)

Here we have \(λ\) is the wavelength, h is Planck's constant, c is the velocity of light and E_g is the energy band gap.

CALCULATION:

Given: The energy band gap, Eg = 1.9 eV

The photon energy in eV using the wavelength in μm, the equation is approximately

\(E (eV) = \frac{1.240}{\lambda (μ m)}\ \)

Now, on putting the given values we have;

\(λ = \frac{1.24}{1.9} \ μ m\)

⇒λ = 0.6526 μm

⇒λ ≈ 652.6 nm

Hence, option 4) is the correct answer.

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