Practice Questions

Q29.The truth table for the circuit given in the figure is: (1) A B Y (2) A B Y 0 0 0 0 0 1 0 1 0 0 1 0 1 0 1 1 0 0 1 1 1 1 1 0 (3) A B Y (4) A B Y 0 0 1 0 0 1 0 1 1 0 1 1 1 0 1 1 0 0 1 1 1 1 1 0

Q29.The least count of the main scale of a screw gauge is 1 mm. The minimum number of divisions on its circular scale required to measure 5 μm diameter of a wire is: (1) 50 (2) 100 (3) 500 (4) 200

Q29.To double the covering range of a TV transmitting tower, its height should be multiplied by: (1) 1 (2) 4 √2 (3) 2 (4) √2

Q30.The wavelength of the carrier waves in a modern optical fiber communication network is close to: (1) 2400 nm (2) 900 nm (3) 600 nm (4) 1500 nm

Q30.The physical sizes of the transmitter and receiver antenna in a communication system are: (1) proportional to carrier frequency (2) independent of both carrier and modulation frequency (3) inversely proportional to modulation frequency (4) inversely proportional to carrier frequency

Q30.A signal Acosωt is transmitted using ν0sinω0t as carrier wave. The correct amplitude modulated (AM) signal is: JEE Main 2019 (09 Apr Shift 1) JEE Main Previous Year Paper (1) ν0sin[ω0(1 + 0.01Asinωt)t] (2) (ν0 + A)cosωt sinω0t (3) ν0 sinω0t + Acosωt (4) ν0sinω0t + A2 sin(ω0 −ω)t + A2 sin(ω0 + ω)t

Q1. The relative error in the determination of the surface area of a sphere is α. The relative error in the determination of its volume is (1) 3 α (2) 2 α 2 3 (3) α (4) 5 α 2

Q1. The density of a material, in the shape of a cube, is determined by measuring three sides of the cube and its mass. If the relative errors in measuring the mass and length are 1. 5% and 1%, respectively, the maximum error in determining the density is: (1) 6 % (2) 2.5 % (3) 3.5 % (4) 4.5 %

Q1. The relative error in the determination of the surface area of a sphere is α. Then the relative error in the determination of its volume is (1) 2 α (2) 2 α 3 3 (3) 3 α (4) α 2

Q2. The percentage errors in quantities P , Q , R and S are 0. 5%, 1%, 3% and 1. 5% respectively in the P 3Q2 measurement of a physical quantity A= . The maximum percentage error in the value of A will be: √RS (1) 6.5 % (2) 7.5 % (3) 6.0 % (4) 8.5 %

Q3. An automobile, traveling at 40 km h−1 , can be stopped at a distance of 40 m by applying brakes. If the same automobile is traveling at 80 km h−1 , the minimum stopping distance in metres is (Assume no skidding): (1) 150 m (2) 100 m (3) 75 m (4) 160 m

Q10.One mole of an ideal monatomic gas is compressed isothermally in a rigid vessel to double its pressure at room temperature, 27oC . The magnitude of work done on the gas will be: (1) 300R (2) 300R ln 2 (3) 300 ln 6 (4) 300R ln 7

Q13.The end correction of a resonance column is 1 cm . If the shortest length resonating with the tuning fork is 10 cm, the next resonating length should be (1) 32 cm (2) 40 cm (3) 28 cm (4) 36 cm JEE Main 2018 (16 Apr Online) JEE Main Previous Year Paper

Q15.The equivalent capacitance between A and B in the circuit is given below. (1) 3. 6 μF (2) 2. 4 μF (3) 4. 9 μF (4) 5. 4 μF

Q15.The equivalent capacitance between A and B in the circuit given below is: (1) 4.9μF (2) 3.6μF (3) 5.4μF (4) 2.4μF

Q17.A heating element has a resistance of 100 Ω at room temperature. When it is connected to a supply of 220 V, a steady current of 2 A passes in it and temperature is 500 oC more than the room temperature. The temperature coefficient of resistance of the heating element is (1) 5 × 10−4 oC−1 (2) 2 × 10−4 oC−1 (3) 1 × 10−4 oC−1 (4) 0.5 × 10−4 oC−1

Q18.A galvanometer with its coil resistance 25 Ω requires a current of 1 mA for its full deflection. In order to construct an ammeter to read up to a current of 2 A the approximate value of the shunt resistance should be: (1) 1.25 × 10−2 Ω (2) 2.5 × 10−3 Ω (3) 2.5 × 10−2 Ω (4) 1.25 × 10−3 Ω

Q20.A charge q is spread uniformly over an insulated loop of radius r. If it is rotated with an angular velocity ω with respect to normal axis then magnetic moment of the loop is: JEE Main 2018 (16 Apr Online) JEE Main Previous Year Paper (1) 3 qωr2 (2) 1 qωr2 2 2 (3) qωr2 (4) 4 qωr2 3

Q21.A coil of cross-sectional area A having n turns is placed in a uniform magnetic field B. When it is rotated with an angular velocity ω, the maximum e.m.f. induced in the coil will be: (1) 3 nBAω (2) 3nBAω 2 (3) nBAω (4) 1 nBAω 2

Q22.For an RLC circuit driven with voltage of amplitude vm and frequency ω0 = √LC1 the current exhibits resonance. The quality factor, Q is given by (1) CR (2) ω0L ω0 R (3) ω0R (4) R L (ω0C) .

Q23.A plane polarized monochromatic EM wave is travelling a vacuum along z direction such that at t = t1 it is found that the electric field is zero at a spatial point z1 . The next zero that occurs in its neighbourhood is at z2 . JEE Main 2018 (15 Apr Shift 2 Online) JEE Main Previous Year Paper The frequency of the electromagnetic wave is: (1) 3×108 (2) 6×108 |z2−z1| |z2−z1| (3) 1.5×108 (4) 1 |z2−z1| t1+ z2−z1 3×108

Q24.Light of wavelength 550 nm falls normally on a slit of width 22.0 × 10−5 cm. The angular position of the second minima from the central maximum will be (in radians): (1) π (2) π 4 8 (3) π (4) π 12 6

Q26.If the de Broglie wavelengths associated with a proton and an α-particle are equal, then the ratio of velocities of the proton and the α-particle will be: (1) 1 : 4 (2) 1 : 2 (3) 4 : 1 (4) 2 : 1

Q29.The number of amplitude-modulated broadcast stations that can be accommodated in a 300 kHz bandwidth for the highest modulating frequency 15 kHz will be: (1) 15 (2) 20 (3) 8 (4) 10

Q29.The reading of the ammeter for a silicon diode in the given circuit is: (1) 13 .5 mA (2) 0 (3) 15 mA (4) 11 .5 mA