Practice Questions

Q14.Following plots show Magnetization ( 𝑀) vs Magnetising field ( 𝐻) and Magnetic susceptibility ( χ ) vs Temperature ( 𝑇) graph : Which of the following combination will be represented by a diamagnetic material? (1) ( b ) , ( c ) (2) ( b ) , ( d ) (3) ( a ) , ( d ) (4) ( a ) , ( c )

Q14.The given potentiometer has its wire of resistance 10 Ω. When the sliding contact is in the middle of the potentiometer wire, the potential drop across 2 Ω resistor is: (1) 10 V (2) 5 V (3) 40 9 V (4) 4011 V

Q14.In a series LCR circuit, the inductive reactance (XL) is 10 Ω and the capacitive reactance (XC) is 4 Ω. The resistance (R) in the circuit is 6 Ω. The power factor of the circuit is : (1) 21 (2) 2√21 (3) 1 (4) √3 √2 2 JEE Main 2021 (18 Mar Shift 2) JEE Main Previous Year Paper

Q14.Your friend is having eye sight problem. She is not able to see clearly a distant uniform window mesh and it appears to her as nonuniform and distorted. The doctor diagnosed the problem as : (1) Astigmatism (2) Myopia with Astigmatism (3) Presbyopia with Astigmatism (4) Myopia and hypermetropia

Q14.A current through a wire depends on time as 𝑖= 𝛼0𝑡+ 𝛽𝑡2, where 𝛼0 = 20 A s-1 and 𝛽= 8 A s-2. Find the charge crossed through a section of the wire in 15 s . (1) 2250 C (2) 11250 C (3) 2100 C (4) 260 C

Q14.Match List - I with List - II. List-I List-II (a) Source of microwave frequency (i) Radioactive decay of nucleus (b) Source of infrared frequency (ii) Magnetron (c) Source of Gamma Rays (iii) Inner shell electrons (d) Source of X -rays (iv) Vibration of atoms and molecules (v) LASER (vi) RC circuit Choose the correct answer from the options given below: (1) (a)-(ii), (b)-(iv), (c)-(vi), (d)-(iii) (2) (a)-(vi), (b)-(iv), (c)-(i), (d)-(v) (3) (a)-(vi), (b)-(v), (c)-(i), (d)-(iv) (4) (a)-(ii), (b)-(iv), (c)-(i), (d)-(iii)

Q14.The resistance of a conductor at 15°C is 16 Ω and at 100°C is 20 Ω. What will be the temperature coefficient of resistance of the conductor? (1) 0. 010°C−1 (2) 0. 033°C−1 (3) 0. 003°C−1 (4) 0. 042°C−1

Q14.Red light differs from blue light as they have : (1) Different frequencies and different wavelengths (2) Different frequencies and same wavelengths (3) Same frequencies and same wavelengths (4) Same frequencies and different wavelengths

Q14.In an ac circuit, an inductor, a capacitor and a resistor are connected in series with XL = R = XC. Impedance of this circuit is : (1) Zero (2) R (3) R√2 (4) 2R2 JEE Main 2021 (31 Aug Shift 1) JEE Main Previous Year Paper

Q15.The electric field in a plane electromagnetic wave is given by, E = 50 sin(500x −10 × 1010t) V m−1 . The velocity of an electromagnetic wave in this medium is: (Given c = the speed of light in vacuum). (1) 23 c (2) c (3) 2c (4) 23 c

Q15.What should be the order of arrangement of de-Broglie wavelength of electron 𝜆e, an 𝛼-particle 𝜆α and proton 𝜆p given that all have the same kinetic energy ? (1) 𝜆𝑒= 𝜆𝑝= 𝜆𝛼 (2) 𝜆e < 𝜆p < 𝜆α (3) 𝜆e > 𝜆p > 𝜆α (4) 𝜆e = 𝜆p > 𝜆α

Q15.A coil is placed in a magnetic field →𝐵 as shown below : → A current is induced in the coil because 𝐵 is : (1) parallel to the plane of coil and increasing with (2) outward and increasing with time time (3) outward and decreasing with time (4) parallel to the plane of coil and decreasing with time + ^j cos𝑘𝑧- 𝜔𝑡 where ^i, ^j

Q15.An electron of mass me and a proton of mass mp = 1836 me are moving with the same speed. The ratio of their de Broglie wavelength λelectron will be : λproton (1) 1836 (2) 18361 (3) 918 (4) 1

Q15.Match List-I with List-II List-i List-II π 2 ; current Phase difference between current and voltage in a purely a i leads resistive AC circuit voltage bPhase difference between current and ii zero voltage in a pure inductive AC circuit Phase difference between current and π 2 ; current lags c iii voltage in a pure capacitive AC circuit voltage dPhase difference between current and iv tan−1( XC−XLR ) voltage in an LCR series circuit Choose the most appropriate answer from the options given below : (1) (a) −(i), (b) −(iii), (c) −(iv), (d) −(ii) (2) (a) −(ii), (b) −(iv), (c) −(iii), (d) −(i) (3) (a) −(ii), (b) −(iii), (c) −(iv), (d) −(i) (4) (a )-( ii ) , (b) −(iii), (c) −(i), (d) −(iv)

Q15.If the source of light used in a Young's double slit experiment is changed from red to violet: (1) consecutive fringe lines will come closer. (2) the fringes will become brighter. (3) the central bright fringe will become a dark (4) the intensity of minima will increase. fringe.

Q15.A cell 𝐸1 of emf 6 V and internal resistance 2Ω is connected with another cell 𝐸2 of emf 4 V and internal resistance 8 Ω (as shown in the figure). The potential difference across points 𝑋 and 𝑌 is: (1) 10 . 0 V (2) 5 . 6 V (3) 2 . 0 V (4) 3 . 6 V

Q15.The refractive index of a converging lens is 1. 4. What will be the focal length of this lens if it is placed in a medium of same refractive index ? (Assume the radii of curvature of the faces of lens are R1 and R2 respectively) (1) 1 (2) Infinite (3) R1R2 (4) Zero R1−R2

Q16.The magnetic susceptibility of a material of a rod is 499. Permeability in vacuum is 4π × 10−7 Hm−1. Absolute permeability of the material of the rod is (1) 4π × 10−4 Hm−1 (2) 2π × 10−4 Hm−1 (3) 3π × 10−4 Hm−1 (4) π × 10−4 Hm−1 JEE Main 2021 (20 Jul Shift 2) JEE Main Previous Year Paper

Q16.A 100Ω resistance, a 0. 1μF capacitor and an inductor are connected in series across a 250 V supply at variable frequency. Calculate the value of inductance of inductor at which resonance will occur. Given that the resonant frequency is 60 Hz. (1) 0. 70H (2) 70. 3 mH (3) 7. 03 × 10−5H (4) 70. 3 H

Q16.What happens to the inductive reactance and the current in a purely inductive circuit if the frequency is halved ? (1) Both, inductive reactance and current will (2) Inductive reactance will be halved and be halved. current will be doubled.. (3) Inductive reactance will be doubled and (4) Both, inducting reactance and current will be current will be halved. doubled JEE Main 2021 (17 Mar Shift 2) JEE Main Previous Year Paper

Q17.A particle is travelling 4 times as fast as an electron. Assuming the ratio of de-Broglie wavelength of a particle to that of electron is 2 : 1, the mass of the particle is :- (1) 1 times the mass of e− (2) 8 times the mass of e− 16 (3) 16 times the mass of e− (4) 18 times the mass of e−

Q17.The expected graphical representation of the variation of angle of deviation ' δ ' with angle of incidence 'i' in a prism is : (1) (2) (3) (4)

Q17.The wavelength of the photon emitted by a hydrogen atom when an electron makes a transition from n = 2 to n = 1 state is: (1) 121. 8 nm (2) 194. 8 nm (3) 490. 7 nm (4) 913. 3 nm JEE Main 2021 (25 Feb Shift 2) JEE Main Previous Year Paper

Q17.In a Young's double slit experiment, the width of the one of the slit is three times the other slit. The amplitude of the light coming from a slit is proportional to the slit-width. Find the ratio of the maximum to the minimum intensity in the interference pattern. JEE Main 2021 (24 Feb Shift 1) JEE Main Previous Year Paper (1) 1: 4 (2) 2: 1 (3) 3: 1 (4) 4: 1

Q17.The light waves from two coherent sources have same intensity I1 = I2 = I0. In interference pattern the intensity of light at minima is zero. What will be the intensity of light at maxima? (1) I0 (2) 2I0 (3) 4I0 (4) 5I0