JEE Physics Semiconductor Electronics MCQs Set 25

Physics Objective Questions and Answers: Semiconductor Electronics

Explore reliable objective questions for Semiconductor Electronics tailored for JEE learners. Utilizing these Physics multiple-choice formats ensures thorough preparation and strengthens problem-solving speed for upcoming school assessments.

Download Semiconductor Electronics MCQs with Answers

View or download the dedicated Semiconductor Electronics MCQ resource below. Practicing these 50 objective questions regularly builds familiarity with standard exam patterns and helps secure higher marks in final Physics evaluations.

Multiple Choice Questions

Question 1: If the two ends of a p-n junction are joined by a wire
(a) there will not be a steady current in the circuit
(b) there will be a steady current from the n-side to the p-side
(c) there will be a steady current from the p-side to the n-side
(d) there may or may not be a current depending upon the resistance of the connecting wire
Show Answer & Explanation

Answer: (a) there will not be a steady current in the circuit

Explanation:
1. There is no source of energy, so no steady current flows (the contact potential adds up to zero around the loop).

Teacher's Note:
1. Recall the basic fact.

Question 2: The ratio of forward biased to reverse biased resistance for pn junction diode is
(a) 10⁻¹ : 1
(b) 10⁻² : 1
(c) 10⁴ : 1
(d) 10⁻⁴ : 1
Show Answer & Explanation

Answer: (d) 10⁻⁴ : 1

Explanation:
1. Forward resistance is small (tens of ohms) while reverse resistance is very large (about 10⁵ to 10⁶ ohm), giving a ratio about 10⁻⁴ : 1.

Teacher's Note:
1. Recall the basic fact.

Question 3: In a full wave rectifier circuit operating from 50 Hz mains frequency, the fundamental frequency in the ripple would be
(a) 25 Hz
(b) 50 Hz
(c) 70.7 Hz
(d) 100 Hz
Show Answer & Explanation

Answer: (d) 100 Hz

Explanation:
1. A full wave rectifier gives two pulses per cycle, so the ripple frequency is 100 Hz.

Teacher's Note:
1. Recall the basic fact.

Question 4: In a semiconductor diode, the barrier potential offers opposition to
(a) holes in P-region only
(b) free electrons in N-region only
(c) majority carriers in both regions
(d) majority as well as minority carriers in both regions
Show Answer & Explanation

Answer: (c) majority carriers in both regions

Explanation:
1. The barrier opposes the flow of majority carriers across the junction.

Teacher's Note:
1. Recall the basic fact.

Question 5: Forward biasing is that in which the applied voltage
(a) increases potential barrier
(b) reduces the potential barrier
(c) is equal to 1.5 volt
(d) None of these
Show Answer & Explanation

Answer: (b) reduces the potential barrier

Explanation:
1. Forward bias opposes the barrier potential and lowers it.

Teacher's Note:
1. Recall the basic fact.

Question 6: The ratio of electron and hole currents in a semiconductor is 7/4 and the ratio of drift velocities of electrons and holes is 5/4, then the ratio of concentrations of electrons and holes will be
(a) \( 5/7 \)
(b) \( 7/5 \)
(c) \( 25/49 \)
(d) \( 49/25 \)
Show Answer & Explanation

Answer: (b) \( 7/5 \)

Explanation:
1. I ∝ n v, so ne/nh = (Ie/Ih)/(ve/vh) = (7/4)/(5/4) = 7/5.

Teacher's Note:
1. Recall the basic fact.

Question 7:
Assertion (A): In semiconductors, thermal collisions are responsible for taking a valence electron to the conduction band.
Reason (R): The number of conduction electrons go on increasing with time as thermal collisions continuously take place.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Show Answer & Explanation

Answer: (c) A is true, but R is false.

Explanation:
1. Thermal energy does excite electrons.
2. The number of conduction electrons does not keep increasing, since recombination balances generation at equilibrium, so the reason is false.

Teacher's Note:
1. Compare the two statements.

Question 8: The average value of output direct current in a full wave rectifier is
(a) \( I_0/\pi \)
(b) \( I_0/2 \)
(c) \( \pi I_0/2 \)
(d) \( 2I_0/\pi \)
Show Answer & Explanation

Answer: (d) \( 2I_0/\pi \)

Explanation:
1. I_dc = 2I₀/π for a full wave rectifier.

Teacher's Note:
1. Recall the basic fact.

Question 9:
Assertion (A): A p-type semiconductor is a positive type crystal.
Reason (R): A p-type semiconductor is an uncharged crystal.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Show Answer & Explanation

Answer: (d) A is false, but R is true.

Explanation:
1. The crystal is electrically neutral, not positively charged, so the assertion is false.
2. The reason is true.

Teacher's Note:
1. Compare the two statements.

Question 10: In V-I characteristic of a p-n junction, reverse biasing results in
(a) leakage current
(b) the current barrier across junction increases
(c) no flow of current
(d) large current
Show Answer & Explanation

Answer: (a) leakage current

Explanation:
1. A very small leakage (minority carrier) current flows under reverse bias.

Teacher's Note:
1. Recall the basic fact.

Question 11: Current gain in common base configuration is less than 1 because
(a) \( I_e \lt I_b \)
(b) \( I_b \lt I_e \)
(c) \( I_c \lt I_e \)
(d) \( I_e \lt I_c \)
Show Answer & Explanation

Answer: (c) \( I_c \lt I_e \)

Explanation:
1. α = Ic/Ie, and Ic is slightly less than Ie since a small part of Ie goes to the base.

Teacher's Note:
1. Recall the basic fact.

Question 12: A transistor is operated in common emitter configuration at Vc = 2 V such that a change in the base current from 100 μA to 300 μA produces a change in the collector current from 10 mA to 20 mA. The current gain is
(a) 50
(b) 75
(c) 100
(d) 25
Show Answer & Explanation

Answer: (a) 50

Explanation:
1. β = ΔIc/ΔIb = 10 mA/200 μA = 50.

Teacher's Note:
1. Recall the basic fact.

Question 13: In an n-type semiconductor, donor valence band is
(a) above the conduction band of the host crystal
(b) close to the valence band of the host crystal
(c) close to the conduction band of the host crystal
(d) below the valence band of the host crystal
Show Answer & Explanation

Answer: (c) close to the conduction band of the host crystal

Explanation:
1. The donor level lies just below the conduction band.

Teacher's Note:
1. Recall the basic fact.

Question 14: Which of these are used for doping? I. A trivalent impurity II. A tetravalent impurity III. A pentavalent impurity IV. A monovalent impurity
(a) I and II
(b) II and IV
(c) I and III
(d) II and III
Show Answer & Explanation

Answer: (c) I and III

Explanation:
1. Trivalent impurities (p-type) and pentavalent impurities (n-type) are used for doping.

Teacher's Note:
1. Recall the basic fact.

Question 15: A zener diode having breakdown voltage equal to 15 V is used in a voltage regulator circuit. A 20 V source is connected through a 250 Ω resistor to a parallel combination of the zener diode and a 1 kΩ load resistor. The current through the diode is
(a) 10 mA
(b) 15 mA
(c) 20 mA
(d) 5 mA
Show Answer & Explanation

Answer: (d) 5 mA

Explanation:
1. Current through the 250 Ω resistor = (20 − 15)/250 = 20 mA.
2. Load current = 15/1000 = 15 mA.
3. Zener current = 20 − 15 = 5 mA.

Teacher's Note:
1. Recall the basic fact.

Question 16: The impurity atoms with which pure silicon may be doped to make it a p-type semiconductor are those of
(a) phosphorus
(b) boron
(c) antimony
(d) nitrogen
Show Answer & Explanation

Answer: (b) boron

Explanation:
1. Boron is trivalent and creates holes. Phosphorus and antimony are pentavalent.

Teacher's Note:
1. Recall the basic fact.

Question 17: In a p-type semiconductor, the acceptor valence band is
(a) close to the valence band of the host crystal
(b) close to conduction band of the host crystal
(c) below the conduction band of the host crystal
(d) above the conduction band of the host crystal
Show Answer & Explanation

Answer: (a) close to the valence band of the host crystal

Explanation:
1. The acceptor level lies just above the valence band.

Teacher's Note:
1. Recall the basic fact.

Question 18: In common base circuit, output resistance is
(a) very high
(b) low
(c) very low
(d) moderate
Show Answer & Explanation

Answer: (a) very high

Explanation:
1. The collector junction is reverse biased, so output resistance is very high.

Teacher's Note:
1. Recall the basic fact.

Question 19: If a small amount of antimony is added to germanium crystal
(a) it becomes a p-type semiconductor
(b) the antimony becomes an acceptor atom
(c) there will be more free electrons than holes in the semiconductor
(d) its resistance is increased
Show Answer & Explanation

Answer: (c) there will be more free electrons than holes in the semiconductor

Explanation:
1. Antimony is pentavalent, a donor. The crystal becomes n-type with more free electrons.

Teacher's Note:
1. Recall the basic fact.

Question 20: In Boolean algebra, Y = A + B implies that
(a) output Y exists when both inputs A and B exist
(b) output Y exists when either input A exists or input B exists or both inputs A and B exist
(c) output Y exists when either input A exists or input B exists but not when both inputs A and B exist
(d) output Y exists when both inputs A and B exists but not when either input A or B exist
Show Answer & Explanation

Answer: (b) output Y exists when either input A exists or input B exists or both inputs A and B exist

Explanation:
1. OR gate: output is 1 if either input or both are 1.

Teacher's Note:
1. Recall the basic fact.

Question 21: In a p-n junction having depletion layer of thickness 10⁻⁶ m the potential across it is 0.1 V. The electric field is
(a) 10⁷ V/m
(b) 10⁻⁶ V/m
(c) 10⁵ V/m
(d) 10⁻⁵ V/m
Show Answer & Explanation

Answer: (c) 10⁵ V/m

Explanation:
1. E = V/d = 0.1/10⁻⁶ = 10⁵ V/m.

Teacher's Note:
1. Recall the basic fact.

Question 22: An oscillator is nothing but an amplifier with
(a) positive feedback
(b) large gain
(c) negative feedback
(d) no feedback
Show Answer & Explanation

Answer: (a) positive feedback

Explanation:
1. Positive feedback sustains oscillations.

Teacher's Note:
1. Recall the basic fact.

Question 23: Pure Si at 500 K has equal number of electron (ne) and hole (nh) concentrations of 1.5 × 10¹⁶ m⁻³. Doping by indium increases nh to 4.5 × 10²² m⁻³. The doped semiconductor is of
(a) n-type with electron concentration ne = 5 × 10²² m⁻³
(b) p-type with electron concentration ne = 2.5 × 10¹⁰ m⁻³
(c) n-type with electron concentration ne = 2.5 × 10²³ m⁻³
(d) p-type having electron concentration ne = 5 × 10⁹ m⁻³
Show Answer & Explanation

Answer: (d) p-type having electron concentration ne = 5 × 10⁹ m⁻³

Explanation:
1. Indium is trivalent, so the material is p-type.
2. ne nh = ni², so ne = (1.5 × 10¹⁶)²/(4.5 × 10²²) = 5 × 10⁹ m⁻³.

Teacher's Note:
1. Recall the basic fact.

Question 24: When the forward bias voltage of a diode is changed from 0.6 V to 0.7 V, the current changes from 5 mA to 15 mA. Then its forward bias resistance is
(a) 0.01 Ω
(b) 0.1 Ω
(c) 10 Ω
(d) 100 Ω
Show Answer & Explanation

Answer: (c) 10 Ω

Explanation:
1. r = ΔV/ΔI = 0.1/(10 × 10⁻³) = 10 Ω.

Teacher's Note:
1. Recall the basic fact.

Question 25: In forward biasing of the p-n junction
(a) the positive terminal of the battery is connected to p-side and the depletion region becomes thick
(b) the positive terminal of the battery is connected to n-side and the depletion region becomes thin
(c) the positive terminal of the battery is connected to n-side and the depletion region becomes thick
(d) the positive terminal of the battery is connected to p-side and the depletion region becomes thin
Show Answer & Explanation

Answer: (d) the positive terminal of the battery is connected to p-side and the depletion region becomes thin

Explanation:
1. Forward bias connects the positive terminal to p-side, and the depletion region narrows.

Teacher's Note:
1. Recall the basic fact.

Free study material for Physics

Download Chapter MCQs: JEE Physics Semiconductor Electronics

About Semiconductor Electronics MCQs for JEE Physics

Test your conceptual understanding of Semiconductor Electronics with these targeted multiple-choice questions. Designed in alignment with the latest JEE curriculum for JEE Physics, these problem sets build accuracy and prepare students for objective exams.

How to Verify Your MCQ Answers

Built using the official NCERT book for JEE, these Physics objective sets provide reliable academic guidance. Pair your practice with our recommended NCERT solutions to master optimal problem-solving approaches.

Enhance Speed with Online MCQ Tests

Explore our broader library of printable assignments, chapter notes, and mock tests designed to support continuous revision and secure higher marks in JEE assessments.

FAQs

Where can I access latest JEE Physics Semiconductor Electronics MCQs Set 25?

You can get most exhaustive JEE Physics Semiconductor Electronics MCQs Set 25 for free on StudiesToday.com. These MCQs for JEE Physics are updated for the 2026-27 academic session as per JEE examination standards.

Are Assertion-Reasoning and Case-Study MCQs included in the Physics JEE material?

Yes, our JEE Physics Semiconductor Electronics MCQs Set 25 include the latest type of questions, such as Assertion-Reasoning and Case-based MCQs. 50% of the JEE paper is now competency-based.

How do practicing Physics MCQs help in scoring full marks in JEE exams?

By solving our JEE Physics Semiconductor Electronics MCQs Set 25, JEE students can improve their accuracy and speed which is important as objective questions provide a chance to secure 100% marks in the Physics.

Do you provide answers and explanations for JEE Physics Semiconductor Electronics MCQs Set 25?

Yes, Physics MCQs for JEE have answer key and brief explanations to help students understand logic behind the correct option as its important for 2026 competency-focused JEE exams.

Can I practice these Physics JEE MCQs online?

Yes, you can also access online interactive tests for JEE Physics Semiconductor Electronics MCQs Set 25 on StudiesToday.com as they provide instant answers and score to help you track your progress in Physics.