Electronic Devices | Physics JEE previous year questions with Solutions

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Topic Question Set

Q 1 :
The acceptor level of a p-type semiconductor is 6 eV. The maximum wavelength of light which can create a hole would be (Given hc = 1242 eVnm.) [2024]

407 nm
207 nm
103.5 nm
414 nm

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(2)

$Energy = \frac{h c}{λ};$

$E = \frac{1242}{λ (nm)} eV \Rightarrow 6 = \frac{1242}{λ (nm)}$

$\Rightarrow λ = \frac{1240}{6} = 207 nm$

Q 2 :
A light emitting diode (LED) is fabricated using GaAs semiconducting material whose band gap is 1.42 eV. The wavelength of light emitted from the LED is: [2024]

650 nm
1243 nm
875 nm
1400 nm

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(3)

$λ (nm) = \frac{1240}{E (eV)}$

$λ = \frac{1240}{1.42} = 875 nm (a pprox .)$

Q 3 :
Consider a $n$ -type semiconductor in which $n_{e}$ and $n_{h}$ are number of electrons and holes, respectively. [2025]

(A) Holes are minority carriers

(B) The dopant is a pentavalent atom

(C) $n_{e} n_{h} \neq n_{i}^{2}$
(where $n_{i}$ is number of electrons or holes in semiconductor when it is intrinsic form)

(D) $n_{e} n_{h} \geq n_{i}^{2}$

(E) The holes are not generated due to the donors

Choose the correct answer from the options given below:

(A), (C), (D) only
(A), (C), (E) only
(A), (B), (E) only
(A), (B), (C) only

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(3)

(A) $n$ type semiconductor holes are minority carriers and $e^{-}$ are majority carriers.

(B) Dopant are pentavalent atom.

(C) $n_{e} \cdot n_{h} = n_{i}^{2}$ for intrinsic semiconductor.

(E) In $n$ type semiconductor, primary source of holes generation are thermal excitation.

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