Practice Questions

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.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.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.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.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.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.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 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.

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.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.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)

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

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

Q17.A parallel beam of light of wavelength 900 nm and intensity 100 Wm−2 is incident on a surface perpendicular to the beam. The number of photons crossing 1 cm2 area perpendicular to the beam in one second is (1) 3 × 1016 (2) 4. 5 × 1016 (3) 4. 5 × 1017 (4) 4. 5 × 1020

Q17.Which is the correct ascending order of wavelengths? (1) λvisible < λX−ray < λgamma−ray < λmicrowave (2) λgamma−ray < λX−ray < λvisible < λmicrowave (3) λX−ray < λgamma−ray < λvisible < λmicrowave (4) λmicrowave < λvisible < λgamma−ray < λX−ray

Q17.Two streams of photons, possessing energies to five and ten times the work function of metal are incident on the metal surface successively. The ratio of the maximum velocities of the photoelectron emitted, in the two cases respectively, will be (1) 1 : 2 (2) 1 : 3 (3) 2 : 3 (4) 3 : 2

Q17.In the following circuit, the correct relation between output (Y ) and inputs A and B will be JEE Main 2022 (28 Jun Shift 1) JEE Main Previous Year Paper (1) Y = A ⋅B (2) Y = A + B (3) Y = A ⋅B (4) Y = A + B

Q17.Given below are two statements : Statement I : Davisson-Germer experiment establishes the wave nature of electrons. Statement II : If electrons have wave nature, they can interfere and show diffraction. In the light of the above statements choose the correct answer from the option given below : (1) Both Statement I and Statement II are true. (2) Both Statement I and Statement II are false. (3) Statement I is true but Statement II is false. (4) Statement I is false but Statement II is true.

Q18.The activity of a radioactive material is 6. 4 × 10−4 curie. Its half life is 5 days. The activity will become 5 × 10−6 curie after (1) 7 days (2) 15 days (3) 25 days (4) 35 days JEE Main 2022 (27 Jul Shift 2) JEE Main Previous Year Paper

Q18.For using a multimeter to identify diode from electrical components, choose the correct statement out of the following about the diode (1) It is two terminal device which conducts current (2) It is two terminal device which conducts current in both directions. in one direction only (3) It does not conduct current gives an initial (4) It is three terminal device which conducts current deflection which decays to zero. in one direction only between central terminal and either of the remaining two terminals

Q18.A radioactive sample decays 7 times its original quantity in 15 minutes. The half-life of the sample is 8 (1) 5 min (2) 7. 5 min (3) 15 min (4) 30 min