Practice Questions

Q15.In series LCR circuit, the capacitance is changed from 𝐶 to 4𝐶. To keep the resonance frequency unchanged, the new inductance should be : 1 (1) reduced by 4𝐿 (2) increased by 2𝐿 (3) reduced by 3 (4) increased to 4𝐿 4𝐿 o

Q15.A plane electromagnetic wave of frequency 35 MHz travels in free space along the X -direction. At a → particular point (in space and time) E = 9. 6ˆj V m−1 . The value of magnetic field at this point is: (1) 3. 2 × 10−8ˆk T (2) 3. 2 × 10−8ˆi (3) 9. 6ˆj T (4) 9. 6 × 10−8ˆk T

Q15.Critical angle of incidence for a pair of optical media is 45∘ . The refractive indices of first and second media are in the ratio: (1) 1 : √2 (2) √2 : 1 (3) 2 : 1 (4) 1 : 2

Q15.A plane EM wave is propagating along x direction. It has a wavelength of 4 mm . If electric field is in y direction with the maximum magnitude of 60Vm−1 , the equation for magnetic field is : (1) Bz = 2 × 10−7 sin [ π2 × 103 (x −3 × 108t)]^kT (2) Bz = 60 sin [ π2 (x −3 × 108t)]^kT (3) Bx = 60 sin [ π2 (x −3 × 108t)]i ^ T (4) Bz = 2 × 10−7 sin [ π2 (x −3 × 108t)]^kT JEE Main 2024 (09 Apr Shift 1) JEE Main Previous Year Paper

Q15.A transformer has an efficiency of 80% and works at 10 V and 4 kW . If the secondary voltage is 240 V, then the current in the secondary coil is: (1) 1 . 59 A (2) 13 . 33 A (3) 1 . 33 A (4) 15 . 1 A

Q15.UV light of 4.13eV is incident on a photosensitive metal surface having work function 3.13eV. The maximum kinetic energy of ejected photoelectrons will be: (1) 4.13eV (2) 3.13eV (3) 1eV (4) 7.26eV

Q16.An alternating voltage of amplitude 40 V and frequency 4kHz is applied directly across the capacitor of 12μF. The maximum displacement current between the plates of the capacitor is nearly : (1) 10 A (2) 12 A (3) 8 A (4) 13 A

Q16.A convex mirror of radius of curvature 30 cm forms an image that is half the size of the object. The object distance is : (1) −45 cm (2) 45 cm (3) −15 cm (4) 15 cm

Q16.Given below are two statements : Statement (I) : When an object is placed at the centre of curvature of a concave lens, image is formed at the centre of curvature of the lens on the other side. Statement (II) : Concave lens always forms a virtual and erect image. In the light of the above statements, choose the correct answer from the options 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

Q16.In a plane EM wave, the electric field oscillates sinusoidally at a frequency of 5 × 1010 Hz and an amplitude of 50 V m – 1. The total average energy density of the electromagnetic field of the wave is : [Use 𝜀0 = 8 . 85 × 10 – 12 C2 N-1 m-2] (1) 1 . 106 × 10 – 8 J m – 3 (2) 4 . 425 × 10 – 8 J m – 3 (3) 2 . 212 × 10 – 8 J m – 3 (4) 2 . 212 × 10 – 10 J m – 3 𝐴

Q16.A proton and an electron are associated with same de-Broglie wavelength. The ratio of their kinetic energies is: (Assume h=6.63 ×10−34 J s, me = 9.0 × 10−31 kg and mp = 1836 times me ) (1) 1 : √1836 (2) 1 : 18361 (3) 1 : 1 (4) 1: 1836 √1836

Q16.If the refractive index of the material of a prism is cot( A2 ), where A is the angle of prism then the angle of minimum deviation will be (1) π −2 A (2) π2 −2 A (3) π −A (4) π2 −A JEE Main 2024 (27 Jan Shift 1) JEE Main Previous Year Paper

Q16.When unpolarized light is incident at an angle of 60° on a transparent medium from air. The reflected ray is completely polarized. The angle of refraction in the medium is (1) 30° (2) 60° (3) 90° (4) 45°

Q16.The electric field of an electromagnetic wave in free space is represented as →E = E0 cos(ωt −kz)ˆi corresponding magnetic induction vector will be : (1) → (2) → E0 B = E0C B = C cos(ωt −kz)ˆj cos(ωt −kz)ˆj (3) → (4) → E0 B = E0C + B = C + cos(ωt kz)ˆj cos(ωt kz)ˆj JEE Main 2024 (30 Jan Shift 1) JEE Main Previous Year Paper

Q16.Given below are two statements : Statement I : When the white light passed through a prism, the red light bends lesser than yellow and violet. Statement II : The refractive indices are different for different wavelengths in dispersive medium. In the light of the above statements, chose the correct answer from the options given below: (1) Statement I is false but Statement II is true (2) Statement I is true but Statement II is false (3) Both Statement I and Statement II are true (4) Both Statement I and Statement II are false

Q16.A hydrogen atom in ground state is given an energy of 10.2eV. How many spectral lines will be emitted due to transition of electrons? (1) 6 (2) 3 (3) 10 (4) 1

Q16.In photoelectric experiment energy of 2.48eV irradiates a photo sensitive material. The stopping potential was measured to be 0.5 V. Work function of the photo sensitive material is : (1) 1.68eV (2) 2.48eV (3) 1.98eV (4) 0.5eV

Q16.For the photoelectric effect, the maximum kinetic energy 𝐸𝑘 of the photoelectrons is plotted against the frequency ( 𝑣) of the incident photons as shown in figure. The slope of the graph gives (1) Ratio of Planck’s constant to electric charge (2) Work function of the metal (3) Charge of electron (4) Planck’s constant

Q16.When a polaroid sheet is rotated between two crossed polaroids then the transmitted light intensity will be maximum for a rotation of : (1) 60° (2) 30° (3) 90° (4) 45°

Q16.For the thin convex lens, the radii of curvature are at 15 cm and 30 cm respectively. The focal length the lens is 20 cm. The refractive index of the material is : (1) 1.2 (2) 1.8 (3) 1.5 (4) 1.4

Q16.If the distance between object and its two times magnified virtual image produced by a curved mirror is 15 cm , the focal length of the mirror must be : (1) 15 cm (2) −12 cm (3) −10 cm (4) 103 cm

Q16.The width of one of the two slits in a Young's double slit experiment is 4 times that of the other slit. The ratio of the maximum of the minimum intensity in the interference pattern is: (1) 1 : 1 (2) 4 : 1 (3) 9 : 1 (4) 16 : 1

Q16.If frequency of electromagnetic wave is 60 MHz and it travels in air along z direction then the corresponding electric and magnetic field vectors will be mutually perpendicular to each other and the wavelength of the wave in m is : (1) 2 . 5 (2) 10 (3) 5 (4) 2

Q16.A proton and an electron have the same de Broglie wavelength. If Kp and Ke be the kinetic energies of proton and electron respectively, then choose the correct relation : (1) Kp > Ke (2) Kp < Ke (3) Kp = Ke (4) Kp = Ke2

Q16.A monochromatic light of wavelength 6000 A is incident on the single slit of width 0 . 01 mm. If the diffraction pattern is formed at the focus of the convex lens of focal length 20 cm, the linear width of the central maximum is : (1) 60 mm (2) 24 mm (3) 120 mm (4) 12 mm