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Standard XII

Physics

Light Emitting Diode

An LED is c...

Question

An $L E D$ is constructed from a pn junction based on a certain semi-conducting material whose energy gap is $1.9 e V$ . Then the wavelength of the emitted light is

2.9 \times 10^{- 9} m

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1.6 \times 10^{- 8} m

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6.5 \times 10^{- 7} m

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9.1 \times 10^{- 5} m

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Solution

The correct option is C $6.5 \times 10^{- 7} m$
Energy gap $E_{g} = 1.9 e V$
Wavelength of light emitted $λ = \frac{h c}{E_{g}}$ nm where $h c = 1240 e V$
$∴$ $λ = \frac{1240}{1.9} \approx 650$ nm $= 6.5 \times 10^{- 7}$ $m$

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Similar questions

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

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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

The correct option is C 6.5×10−7mEnergy gap Eg=1.9eVWavelength of light emitted λ=hcEg nm where hc=1240eV∴ λ=12401.9≈650 nm =6.5×10−7 m

An $L E D$ is constructed from a pn junction based on a certain semi-conducting material whose energy gap is $1.9 e V$ . Then the wavelength of the emitted light is

The correct option is C $6.5 \times 10^{- 7} m$
Energy gap $E_{g} = 1.9 e V$
Wavelength of light emitted $λ = \frac{h c}{E_{g}}$ nm where $h c = 1240 e V$
$∴$ $λ = \frac{1240}{1.9} \approx 650$ nm $= 6.5 \times 10^{- 7}$ $m$