JEE Main Semiconductor Questions with Solutions - Download PDF

JEE main semiconductor questions consist of queries related to electricity, insulator, electrical conductivity, resistance, temperature, metals, power points and so on. These questions are crucial for the exam and must be practised thoroughly.

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JEE Main Semiconductor Questions with Answer Keys - Download PDF
Top JEE Main Semiconductor Questions with Answer

JEE main 2024 semiconductor questions are derived from the electricity chapter in class 11 and 12 physics syllabus. It consists of topics like intrinsic and extrinsic conductors, energy band gap, resistance etc. Candidates must practice the JEE main semiconductor questions carefully to get good scores in the JEE main exam for physics.

The JEE Main Session 1 examination was conducted from Jan 24 to Feb 1, 2024. Session 2 will be held from Apr 4 to Apr 15, 2024. The admit cards for the exams scheduled on Apr 4, Apr 5, and Apr 6, 2024, have been released by the NTA on the official website on Mar 31, 2024. The admit cards for the other exams of Session 2 will be released soon.

JEE Main Semiconductor Questions with Answer Keys - Download PDF

The JEE Main semiconductor questions with solutions that are asked in JEE Main 2024 are mentioned in detail and are added to the PDF below, and students can directly download the PDF by clicking on the link.

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Top JEE Main Semiconductor Questions with Answer

Top JEE Main Semiconductor Questions with answers are provided below step-wise for students; these questions are frequently asked in JEE Main 2024. The weightage of semiconductor in the exam is almost 4 to 5 questions asked in each shift.

Question 1: The energy band gap is maximum in

(a) metals

(b) superconductors

(d) semiconductors

Answer: (c) The energy band gap is maximum in insulators

Question 2: A piece of copper and another of germanium are cooled from room temperature to 77 K, the resistance of

(a) each of them increases

(b) each of them decreases

(d) copper increases and germanium decreases

Solution

Copper is a conductor. Germanium is a semiconductor. When cooled, the resistance of copper decreases and that of germanium increases.

Answer: (c) copper decreases and germanium increases

Question 3: In the common base mode of a transistor, the collector current is 5.488 mA for an emitter current of 5.60 mA. The value of the base current amplification factor (β) will be

(a) 48

(b) 49

(d) 51

Solution

β=Ic/Ib = Ic/(Ie – Ic) = 5.488/(5.60 – 5.488) = 5.488/ 0.112 = 49

Answer: (b) 49

Question 4: Carbon, silicon and germanium have four valence electrons each. At room temperature which one of the following statements is most appropriate?

(a) The number of free electrons for conduction is significant only in Si and Ge but small in C

(b) The number of free conduction electrons is significant in C but small in Si and Ge

(d) The number of free electrons for conduction is significant in all three

Solution

Carbon (C), silicon (Si) and germanium (Ge) have the same lattice structure and their valence electrons are 4. For C, these electrons are in the second orbit, for Si it is third and for germanium, it is the fourth orbit. In solid-state, the higher the orbit, the greater the possibility of overlapping of energy bands. Ionization energies are also less therefore Ge has more conductivity compared to Si. Both are semiconductors. Carbon is an insulator.

Answer: (a) The number of free electrons for conduction is significant only in Si and Ge but small in C

Question 5: In the ratio of the concentration of electrons that of holes in a semiconductor is 7/5 and the ratio of currents is 7/4 then what is the ratio of their drift velocities?

(a) 4/7

(b) 5/8

(d) 5/4

Solution

Drift velocity, Vd = I/nAe

(vd)electron/(vd)hole = (Ie/Ih)(nh/ne) = (7/4) x (5/7) = 5/4

Answer: (d) 5/4

Question 6: At absolute zero, silicon (Si) acts as

(a) non-metal

(b) metal

(d) none of these

Solution

Semiconductors like silicon (Si) and germanium (Ge) act as insulators at low temperature.

Answer: (c) insulator

Question 7: The mobility of electrons in a semiconductor is defined as the ratio of their drift velocity to the applied electric field. If for an n-type semiconductor, the density of electrons is 1019 m–3 and their mobility is 1.6 m2 /(V-s) then the resistivity of the semiconductor (since it is an n-type semiconductor contribution of holes is ignored) is close to

(a) 0.2 m

(b) 4 m

(d) 0.4 m

Solution

J = neVd

Resistivity, ρ = E/j = E/neVd = 1/ne(vd/E) = 1/neμe

Resistivity, 1/(1019 x 1.6 x 10-19 x 1.6) = 0.39 Ω m = 0.4 Ω m

Answer: (d) 0.4 m

Question 8: The electrical conductivity of a semiconductor increases when electromagnetic radiation of a wavelength shorter than 2480 nm is incident on it. The bandgap in (eV) for the semiconductor is

(a) 0.5 eV

(b) 0.7 eV

(d) 2.5 eV

Solution

Band gap = Energy of photon of = 2480 nm

Energy = (hc/λ) J = (hc/λe) eV

Band gap = ([(6.63 x 10-34) x (3 x 108)]/[(2480 x 10-9) x (1.6 x 10-19)]) = 0.5 eV

Answer: (a) 0.5 eV

Question 9: The difference in the variation of resistance with temperature in a metal and a semiconductor arises essentially due to the difference in the

(a) crystal structure

(b) variation of the number of charge carriers with temperature

(d) variation of scattering mechanism with temperature

Answer: (b) variation of the number of charge carriers with temperature

Question 10: A strip of copper and another germanium are cooled from room temperature to 80 K. The resistance of

(a) each of these decreases

(b) copper strip increases and that of germanium decreases

(d) each of these increases.

Solution

Copper is conductor and germanium is a semiconductor. When cooled, the resistance of copper strip decreases and that of germanium increases.

Answer: (c) copper strip decreases and that of germanium increases