Three phtodiodes D 1, D 2 and D 3 are made of semiconductors having band gaps of 2.5 eV, 2 eV and 3 eV respectively. Which one will be able to detect light of wavelength 600 nm?

Question

Three phtodiodes D 1, D 2 and D 3 are made of semiconductors having band gaps of 2.5 eV, 2 eV and 3 eV respectively. Which one will be able to detect light of wavelength 600 nm? (A) D 1 only (B) both D 1 and D 3 (C) D 2 only (D) All the three diodes

Tardigrade Admin · Accepted Answer

E 1=2.5 eV E 2=2 eV E 3=3 eV λ=600 nm ∴ E =(1242/λ nm )=(1242/600) eV =2.07 eV ( E 1 and E 3 is > E Only D 2 will detect

Q. Three phtodiodes $D_{1}, D_{2}$ and $D_{3}$ are made of semiconductors having band gaps of $2.5 e V$ , $2 e V$ and $3 e V$ respectively. Which one will be able to detect light of wavelength $600 nm ?$

$D_{1}$ only

both $D_{1}$ and $D_{3}$

$D_{2}$ only

All the three diodes

$E_{1} = 2.5 e V$
$E_{2} = 2 e V$
$E_{3} = 3 e V$
$λ = 600 nm$
$∴ E = \frac{1242}{λ _{nm}} = \frac{1242}{600} e V$
$= 2.07 e V$
$(E_{1}$ and $E_{3}$ is $> E$
Only $D_{2}$ will detect

Q. Three phtodiodes D1​,D2​ and D3​ are made of semiconductors having band gaps of 2.5eV, 2eV and 3eV respectively. Which one will be able to detect light of wavelength 600nm?

D1​ only

both D1​ and D3​

D2​ only