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An LED is constructed from a pn junction...

An LED is constructed from a pn junction based on a certain semi-conducting material whose energy gap is 1.9 eV. Then the wavelength of the emitted light is

A

`9.1 xx 10^(-5)m`

B

`6.5 xx 10^(-7)m`

C

`1.6 xx 10^(-8)m`

D

`2.9 xx 10^(-9)m`

Text Solution

Verified by Experts

The correct Answer is:
B
`E_(g)= (hc)/(lamda) rArr lamda= (hc)/(E_(g))= (6.63 xx 10^(-34) xx 3 xx 10^(8))/(1.9 xx 1.6 xx 10^(-19))= 6.5 xx 10^(-7)m`
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