Practice Questions

Q12.Given below are two statements. Statement I : Electric potential is constant within and at the surface of each conductor. Statement II : Electric field just outside a charged conductor is perpendicular to the surface of the conductor at every point. JEE Main 2022 (29 Jul Shift 1) JEE Main Previous Year Paper In the light of the above statements, choose the most appropriate answer from the options give below. (1) Both statement I and statement II are correct (2) Both statement I and statement II are incorrect (3) Statement I is correct but statement II is incorrect (4) Statement I is incorrect but and statement II is correct

Q12.The current sensitivity of a galvanometer can be increased by : (A) decreasing the number of turns (B) increasing the magnetic field (C) decreasing the area of the coil (D) decreasing the torsional constant of the spring Choose the most appropriate answer from the options given below : (1) (B) and (C) only (2) (C) and (D) only (3) (A) and (C) only (4) (B) and (D) only

Q12.A triangular shaped wire carrying 10 A current is placed in a uniform magnetic field of 0. 5 T, as shown in figure. The magnetic force on segment CD is (Given BC = CD = BD = 5 cm). (1) 0. 126 N (2) 0. 312 N (3) 0. 216 N (4) 0. 245 N

Q12.The magnetic moment of an electron 𝑒 revolving in an orbit around nucleus with an orbital angular momentum is given by 𝑒𝐿 𝑒𝐿 - (1) →𝜇𝐿= 2 𝑚 (2) →𝜇𝐿= 2 𝑚 (3) 𝑒 →𝐿 (4) 2𝑒 →𝐿 - →𝜇𝐿= 𝑚 →𝜇𝐿= 𝑚

Q12.If wattless current flows in the AC circuit, then the circuit is : (1) Purely Resistive circuit (2) Purely Inductive circuit (3) LCR series circuit (4) RC series circuit only 𝑡- 𝑥

Q12.A parallel plate capacitor is formed by two plates each of area 30π cm2 separated by 1 mm. A material of dielectric strength 3. 6 × 107 V m−1 is filled between the plates. If the maximum charge that can be stored on the capacitor without causing any dielectric breakdown is 7 × 10−6 C, the value of dielectric constant of the material is : [Use 1 = 9 × 109 N m2 C−2 ] 4πεo (1) 1. 66 (2) 1. 75 (3) 2. 25 (4) 2. 33

Q12.Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. Assertion A: Alloys such as constantan and manganin are used in making standard resistance coils. Reason R: Constantan and manganin have very small value of temperature coefficient of resistance. In the light of the above statements, choose the correct answer from the options given below. (1) Both A and R are true and R is the correct (2) Both A and R are true but R is NOT the correct explanation of A explanation of A. (3) A is true but R is false. (4) A is false but R is true.

Q13.A bar magnet having a magnetic moment of 2. 0 × 105 J T−1 , is placed along the direction of uniform magnetic field of magnitude B = 14 × 10−5 T. The work done in rotating the magnet slowly through 60° from the direction of field is (1) 14 J (2) 8 J (3) 4 J (4) 1. 4 J ∘

Q13.Two parallel, long wires are kept 0. 20 m apart in vacuum, each carrying current of x A in the same direction. If the force of attraction per meter of each wire is 2 × 10−6 N , then the value of x is approximately (1) 1 (2) 2. 4 (3) 1. 4 (4) 2

Q13.A proton and an alpha particle of the same velocity enter in a uniform magnetic field which is acting perpendicular to their direction of motion. The ratio of the radii of the circular paths described by the alpha particle and proton is (1) 4 : 1 (2) 2 : 1 (3) 1 : 2 (4) 1 : 4

Q14.At a certain place the angle of dip is 30° and the horizontal component of earth's magnetic field is 0. 5 G . The earth's total magnetic field (in G), at that certain place, is JEE Main 2022 (29 Jun Shift 1) JEE Main Previous Year Paper (1) 1 (2) 1 √3 2 (3) √3 (4) 1

Q14.To increase the resonant frequency in series LCR circuit, (1) Source frequency should be increased (2) Another resistance should be added in series with the first resistance. (3) Another capacitor should be added in series with (4) The source frequency should be decreased the first capacitor

Q14.The susceptibility of a paramagnetic material is 99. The permeability of the material in Wb /A −m, is [Permeability of free space μ0 = 4π × 10−7 Wb /A −m] (1) 4π × 10−5 (2) 4π × 10−6 (3) 4π × 10−7 (4) 4π × 10−4

Q14.A transformer operating at primary voltage 8 kV and secondary voltage 160 V serves a load of 80 kW. Assuming the transformer to be ideal with purely resistive load and working on unity power factor, the loads in the primary and secondary circuit would be (1) 800 Ω and 1. 06 Ω (2) 10 Ω and 500 Ω (3) 800 Ω and 0. 32 Ω (4) 1. 06 Ω and 500 Ω

Q14.In a series LR circuit XL = R and power factor of the circuit is P1 . When capacitor with capacitance C such that XL = XC is put in series, the power factor becomes P2 . The ratio P1 is P2 (1) 1 (2) 1 2 √2 (3) √3 (4) 2 : 1 √2

Q14.The aperture of the objective is 24. 4 cm. The resolving power of this telescope, if a light of wavelength ∘ 2440 A is used to see the object will be (1) 8. 1 × 106 (2) 10. 0 × 107 (3) 8. 2 × 105 (4) 1. 0 × 10−8

Q14.The vertical component of the earth's magnetic field is 6 × 10-5 T at any place where the angle of dip is 37°. 3 The earth's resultant magnetic field at that place will be (Given tan37° = 4) (1) 8 × 10-5 T (2) 6 × 10-5 T (3) 5 × 10-4 T (4) 1 × 10-4 T

Q15.The magnetic field at the centre of a circular coil of radius r, due to current I flowing through it, is B. The magnetic field at a point along the axis at a distance r from the centre is : 2 (1) B (2) 2B 2 (3) 2 3 (4) 2 3 B B ( √5 ) ( √3 )

Q15.The current flowing through an ac circuit is given by I = 5 sin(120πt) A. How long will the current take to reach the peak value starting from zero? (1) 1 s (2) 60 s 60 (3) 120 1 s (4) 2401 s

Q15.Match List - I with List - II List-I List-II (a) UV rays (i) Diagnostic tool in medicine (b) X -rays (ii) Water purification (c) Microwave (iii) Communication, Radar (d) Infrared wave (iv) Improving visibility in foggy days Choose the correct answer from the options given below : (1) (a) −(iii), (b) −(ii), (c) −(i), (d) −(iv) (2) (a) −(ii), (b) −(i), (c) −(iii), (d) −(iv) (3) (a) −(ii), (b) −(iv), (c) −(iii), (d) −(i) (4) (a) −(iii), (b) −(i), (c) −(ii), (d) −(iv)

Q15.The oscillating magnetic field in a plane electromagnetic wave is given by 𝐵𝑦= 5 × 10-6sin1000𝜋5𝑥- 4 × 108𝑡 T. The amplitude of electric field will be (1) 15 × 102Vm-1 (2) 5 × 10-6Vm-1 (3) 16 × 1012Vm-1 (4) 4 × 102Vm-1

Q15.The soft-iron is a suitable material for making an electromagnet. This is because soft-iron has (1) low coercivity and high retentivity. (2) low coercivity and low permeability. (3) high permeability and low retentivity. (4) high permeability and high retentivity.

Q16.Light wave travelling in air along x-direction is given by Ey = 540 sin π × 104(x −ct) V m−1 . Then, the peak value of magnetic field of wave will be (Given c = 3 × 108 m s−1 ) (1) 18 × 10−7 T (2) 54 × 10−7 T (3) 54 × 10−8 T (4) 18 × 10−8 T

Q16.In normal adjustment, for a refracting telescope, the distance between objective and eye piece is 30 cm. The focal length of the objective, when the angular magnification of the telescope is 2, will be: (1) 20 cm (2) 30 cm (3) 10 cm (4) 15 cm 1 . 227

Q16.Which of the following statement is correct? (1) In primary rainbow, observer sees red colour on (2) In primary rainbow, observer sees violet colour the top and violet on the bottom on the top and red on the bottom (3) In primary rainbow, light wave suffers total (4) Primary rainbow is less bright than secondary internal reflection twice before coming out of rainbow. water drops