Electronic Devices | Physics JEE previous year questions with Solutions

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.

Q 4 :

Statement I: When a Si sample is doped with Boron, it becomes P type and when doped by Arsenic it becomes N-type semi conductor such that P-type has excess holes and N-type has excess electrons.

Statement II: When such P-type and N-type semi-conductors are fused to make a junction, a current will automatically flow which can be detected with an externally connected ammeter.

In the light of above statements, choose the most appropriate answer from the options given below. [2023]

Statement I is correct but statement II is incorrect
Both Statement I and statement II are incorrect
Statement I is incorrect but statement II is correct
Both Statement I and statement II are correct

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(1)

Statement – I is correct
When P-N junction is formed an electric field is generated form N-side to P-side due to which barrier potential arises and majority charge carrier can not flow through the junction due to barrier potential so current is zero unless we apply forward bias voltage.

Q 5 :

The effect of increase in temperature on the number of electrons in conduction band $(n_{e})$ and resistance of a semiconductor will be as [2023]

Both $n_{e}$ and resistance decrease
Both $n_{e}$ and resistance increase
$n_{e}$ increases, resistance decreases
$n_{e}$ decreases, resistance increases

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(3)

As temperature increases, more electron excite to conduction band and hence conductivity increases, therefore resistance decreases.

Q 6 :

Match the List I with List II [2023]

List I List II

A. Intrinsic Semiconductor I. Fermi-level near valence band

B. n-type semiconductor II. Fermi-level at middle

C. p-type semiconductor III. Fermi-level near conduction band

D. Metals IV. Fermi-level inside conduction band

Choose the correct answer from the options given below:

(A) → I, (B) → II, (C) → III, (D) → IV
(A) → II, (B) → I, (C) → III, (D) → IV
(A) → II, (B) → III, (C) → I, (D) → IV
(A) → III, (B) → I, (C) → II, (D) → IV

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(3)

(A) Intrinsic semiconductor → II

(B) $n$ -type semiconductor → III

(C) $p$ -type semiconductor → I

(D) Metals → IV

Q 7 :

The resistivity $(ρ)$ of semiconductor varies with temperature. Which of the following curve represents the correct behavior [2023]

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(2)

With rise in temperature, number density $(n)$ of electrons and holes increases for semiconductors.

As $m, e, τ$ are constant

$ρ \propto \frac{1}{n} \Rightarrow ρ \propto \frac{1}{T} [Rectangular hyperbola]$

Q 8 :

A voltage regulating circuit consisting of a Zener diode, having break-down voltage of 10 V and maximum power dissipation of 0.4 W, is operated at 15 V. The approximate value of protective resistance in this circuit is ______ $Ω$ . [2026]

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(125)

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]

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]

Q 5 :

The effect of increase in temperature on the number of electrons in conduction band $(n_{e})$ and resistance of a semiconductor will be as [2023]

Q 7 :

The resistivity $(ρ)$ of semiconductor varies with temperature. Which of the following curve represents the correct behavior [2023]

Q 8 :

A voltage regulating circuit consisting of a Zener diode, having break-down voltage of 10 V and maximum power dissipation of 0.4 W, is operated at 15 V. The approximate value of protective resistance in this circuit is ______ $Ω$ . [2026]

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	List I		List II
A.	Intrinsic Semiconductor	I.	Fermi-level near valence band
B.	n-type semiconductor	II.	Fermi-level at middle
C.	p-type semiconductor	III.	Fermi-level near conduction band
D.	Metals	IV.	Fermi-level inside conduction band