Question

Calculate the wavelength of radiation emitted by an LED made up of a semiconducting material with band gap energy 2.8 eV.

Answer 1

Given:

Band gap energy $E_{g} = 2.8$ eV

To Find:

Wavelength of radiation.

For calculating the wavelength of light,

According to the planck's law,

   $E_{g} = \frac{hc}{\lambda}$

Where $h =$ planck constant = $6.626 \times 10^{-34}$, $c = 3 \times 10^{8} \frac{m}{s}$

   $\lambda = \frac{hc}{E_{g} }$

   $\lambda = \frac{6.626 \times 10^{-34} \times 3 \times 10^{8} }{2.8 \times 1.6 \times 10^{-19} }$

   $\lambda = 4.437 \times 10^{-7}$m

Therefore, the wavelength of radiation emitted by LED is $4.437 \times 10^{-7}$m

Answer 2

Explanation:

Band gap energy E_{g} = 2.8E

g

=2.8 eV

To Find:

Wavelength of radiation.

For calculating the wavelength of light,

According to the planck's law,

E_{g} = \frac{hc}{\lambda}E

g

=

λ

hc

Where h =h= planck constant = 6.626 \times 10^{-34}6.626×10

−34

, c = 3 \times 10^{8} \frac{m}{s}c=3×10

8

s

m

\lambda = \frac{hc}{E_{g} }λ=

E

g

hc

\lambda = \frac{6.626 \times 10^{-34} \times 3 \times 10^{8} }{2.8 \times 1.6 \times 10^{-19} }λ=

2.8×1.6×10

−19

6.626×10

−34

×3×10

8

\lambda = 4.437 \times 10^{-7}λ=4.437×10

−7

m

Therefore, the wavelength of radiation emitted by LED is 4.437 \times 10^{-7}4.437×10

−7

m