Practice Questions

Q19.The resistivity ( 𝜌) of semiconductor varies with temperature. Which of the following curve represents the correct behaviour? (1) (2) (3) (4)

Q19.A massage signal of frequency 3 kHz is used to modulate a carrier signal of frequency 1 . 5 MHz. The bandwidth of the amplitude modulated wave is (1) 6 MHz (2) 6 kHz (3) 3 MHz (4) 3 kHz

Q19.Figure shows a part of an electric circuit. The potentials at points a, b and c are 30 V, 12 V and 2 V respectively. The current through the 20 Ω resistor will be, (1) 1. 0 A (2) 0. 4 A (3) 0. 6 A (4) 0. 2 A

Q19.The effect of increase in temperature on the number of electrons in conduction band ( 𝑛𝑒) and resistance of a semiconductor will be as: JEE Main 2023 (31 Jan Shift 1) JEE Main Previous Year Paper (1) Both 𝑛𝑒 and resistance decrease (2) Both 𝑛𝑒 and resistance increase (3) 𝑛𝑒 increases, resistance decreases (4) 𝑛𝑒 decreases, resistance increases

Q19.Match the List I with List II List I List II AIntrinsic I Fermi-level near valence band Semiconductor Fermi-level at middle of valence and conduction B n-type semiconductor II band C p-type semiconductor III Fermi-level near conduction band DMetals IVFermi-level inside conduction band Choose the correct answer from the options given below: (1) (A) → I, (B) → II, (C) → III, (D) → IV (2) (A) → II, (B) → I, (C) → III, (D) → IV (3) (A) → II, (B) → III, (C) → I, (D) → IV (4) (A) → III, (B) → I, (C) → II, (D) → IV

Q19.The output waveform of the given logical circuit for the following inputs 𝐴 and 𝐵 as shown below, is JEE Main 2023 (30 Jan Shift 1) JEE Main Previous Year Paper (1) (2) (3) (4)

Q19.Match List I with List II List – I List – II (Current configuration) (Magnetic field at point O ) + A I. B0 = μ0I4πr [π 2] JEE Main 2023 (25 Jan Shift 1) JEE Main Previous Year Paper B II. B0 = μ04 Ir C III. B0 = μ0I2πr [π −1] + D IV. B0 = μ0I4πr [π 1] Choose the correct answer from the option given below: (1) A-III, B-IV, C-I, D-II (2) A-I, B-III, C-IV, D-II (3) A-III, B-I, C-IV, D-II (4) A-II, B-I, C-IV, D-III

Q19.In the given circuit the value of I1+I3 is: I2

Q20.A square loop of area 25 cm2 has a resistance of 10 Ω . The loop is placed in uniform magnetic field of magnitude 40. 0 T . The plane of loop is perpendicular to the magnetic field. The work done in pulling the loop out of the magnetic field slowly and uniformly in 1. 0 sec, will be JEE Main 2023 (29 Jan Shift 2) JEE Main Previous Year Paper (1) 2. 5 × 10−3 J (2) 1. 0 × 10−3 J (3) 1. 0 × 10−4 J (4) 5 × 10−3 J

Q20.Certain galvanometers have a fixed core made of non magnetic metallic material. The function of this metallic material is JEE Main 2023 (08 Apr Shift 1) JEE Main Previous Year Paper (1) to oscillate the coil in magnetic field for longer (2) to bring the coil to rest quickly period of time (3) to produce large deflecting torque on the coil (4) to make the magnetic field radial

Q20.A current carrying rectangular loop PQRS is made of uniform wire. The length PR = QS = 5 cm and PQ = RS = 100 cm. If ammeter current reading changes from I to 2I , the ratio of : f PQ)2I is: magnetic forces per unit length on the wire PQ due to wire RS in the two cases respectively (f PQI JEE Main 2023 (30 Jan Shift 2) JEE Main Previous Year Paper (1) 1 : 2 (2) 1 : 4 (3) 1 : 5 (4) 1 : 3

Q20.The height of transmitting antenna is 180 m and the height of the receiving antenna is 245 m . The maximum distance between them for satisfactory communication in line of sight will be: (given R = 6400 km ) JEE Main 2023 (15 Apr Shift 1) JEE Main Previous Year Paper (1) 96 km (2) 56 km (3) 48 km (4) 104 km

Q20.Find the mutual inductance in the arrangement, when a small circular loop of wire of radius R is placed inside a large square loop of wire of side L(L ≫R) . The loops are coplanar and their centres coincide : JEE Main 2023 (29 Jan Shift 1) JEE Main Previous Year Paper (1) M = √2μ0R2L (2) M = 2√2μ0RL2 (3) M = 2√2μ0R2L (4) M = √2μ0RL2

Q20.The ratio of magnetic field at the centre of a current carrying coil of radius r to the magnetic field at distance r from the centre of coil on its axis is √x : 1 . The value of x is _____.

Q20.To radiate EM signal of wavelength 𝜆 with high efficiency, the antennas should have a minimum size equal to: (1) 2𝜆 (2) 𝜆 2 (3) 𝜆 (4) 𝜆 4

Q20.Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A: A bar magnet dropped through a metallic cylindrical pipe takes more time to come down compared to a non-magnetic bar with same geometry and mass. Reason R : For the magnetic bar, Eddy currents are produced in the metallic pipe which oppose the motion of the magnetic bar. In the light of the above statements, choose the correct answer from the options given below JEE Main 2023 (11 Apr Shift 2) JEE Main Previous Year Paper (1) A is false but R is true (2) Both A and R are true and R is the correct explanation of A (3) A is true but R is false (4) Both A and R are true and R is NOT the correct explanation of A

Q20.A single turn current loop in the shape of a right angle triangle with sides 5 cm, 12 cm, 13 cm is carrying a current of 2 A . The loop is in a uniform magnetic field of magnitude 0. 75 T whose direction is parallel to the current in the 13 cm side of the loop. The magnitude of the magnetic force on the 5 cm side will be 130x N . The value of x is _______.

Q20.Which of the following frequencies does not belong to FM broadcast. (1) 106 𝑀𝐻𝑧 (2) 64 𝑀𝐻𝑧 (3) 99 𝑀𝐻𝑧 (4) 89 𝑀𝐻𝑧

Q20.A carrier wave of amplitude 15 V is modulated by a sinusoidal base band signal of amplitude 3 V. The ratio of maximum amplitude to minimum amplitude in an amplitude modulated wave is 3 (1) 2 (2) 2 (3) 1 (4) 5

Q20.A compass needle oscillates 20 times per minute at a place where the dip is 30o and 30 times per minute where the dip is 60o . The ratio of total magnetic field due to the earth at two places respectively is 4 . The value of √x x is

Q20.A transmitting antenna is kept on the surface of the earth. The minimum height of receiving antenna required to receive the signal in line of sight at 4 km distance from it is 𝑥× 10-2 m. The value of 𝑥 is _____. (Let, radius of earth 𝑅= 6400 km) (1) 125 (2) 1250 (3) 12 . 5 (4) 1 . 25

Q20.A coil is placed in magnetic field such that plane of coil is perpendicular to the direction of magnetic field. The magnetic flux through a coil can be changed: A. By changing the magnitude of the magnetic field within the coil. B. By changing the area of coil within the magnetic field. C. By changing the angle between the direction of magnetic field and the plane of the coil. D. By reversing the magnetic field direction abruptly without changing its magnitude. Choose the most appropriate answer from the options given below: (1) A and B only (2) A, B and C only (3) A, B and D only (4) A and C only

Q20.In an experiment with vernier callipers of least count 0 . 1 mm, when two jaws are joined together the zero of vernier scale lies right to the zero of the main scale and 6th division of vernier scale coincides with the main scale division. While measuring the diameter of a spherical bob, the zero of vernier scale lies in between 3 . 2 cm and 3 . 3 cm marks and 4th division of vernier scale coincides with the main scale division. The diameter of bob is measured as (1) 3 . 22 cm (2) 3 . 18 cm (3) 3 . 26 cm (4) 3 . 25 cm JEE Main 2023 (10 Apr Shift 2) JEE Main Previous Year Paper

Q20.The amplitude of 15sin ( 1000π𝑡) is modulated by 10sin ( 4π𝑡) signal. The amplitude modulated signal contains frequency (ies) of ( 𝐴) 500 Hz ( 𝐵) 2 Hz ( 𝐶) 250 Hz ( 𝐷) 498 Hz ( 𝐸) 502 Hz Choose the correct answer from the options given below: (1) A only (2) A, D and E only (3) B only (4) A and B only

Q20.A sinusoidal carrier voltage is amplitude modulated. The resultant amplitude modulated wave has maximum and minimum amplitude of 120 V and 80 V respectively. The amplitude of each side band is : (1) 15 V (2) 10 V (3) 20 V (4) 5 V