Practice Questions

Q28.A light ray is incident, at an incident angle θ1 , on the system of two plane mirrors M1 and M2 having an inclination angle 75° between them (as shown in figure). After reflecting from mirror M1 it gets reflected back by the mirror M2 with an angle of reflection 30° . The total deviation of the ray will be _____ degree.

Q28.Two radioactive materials 𝐴 and 𝐵 have decay constants 25𝜆 and 16𝜆 respectively. If initially they have the 1 same number of nuclei, then the ratio of the number of nuclei of 𝐵 to that of A will be "𝑒" after a time 𝑎𝜆. The JEE Main 2022 (29 Jul Shift 2) JEE Main Previous Year Paper value of 𝑎 is _____ .

Q28.In the given figure, the face 𝐴𝐶 of the equilateral prism is immersed in a liquid of refractive index 𝑛. For incident angle 60° at the side 𝐴𝐶, the refracted light beam just grazes along face 𝐴𝐶. The refractive index of √𝑥 the liquid 𝑛= . The value of 𝑥 is _____ . 4 (Given refractive index of glass = 1 . 5)

Q28.A sample contains 10−2 kg each of two substances A and B with half lives 4 s and 8 s respectively. The ratio of their atomic weights is 1 : 2 . The ratio of the amounts of A and B after 16 s is 100x . The value of x is _____ .

Q28.In the given figure of meter bridge experiment, the balancing length AC corresponding to null deflection of the galvanometer is 40 cm. The balancing length, if the radius of the wire AB is doubled, will be _____ cm. JEE Main 2022 (27 Jul Shift 2) JEE Main Previous Year Paper → +

Q28.In Young's double slit experiment the two slits are 0. 6 mm distance apart. Interference pattern is observed on a screen at a distance 80 cm from the slits. The first dark fringe is observed on the screen directly opposite to one of the slits. The wavelength of light will be _____ nm.

Q28.A parallel beam of light is allowed to fall on a transparent spherical globe of diameter 30 cm and refractive index 1. 5 . The distance from the centre of the globe at which beam of light can converge is _____ mm. Q29. √d1 and √d2 are the impact parameters corresponding to scattering angles 60° and 90° respectively, when an α particle is approaching a gold nucleus. For d1 = xd2 , the value of x will be _____ .

Q28.To light, a 50 W, 100 V lamp is connected, in series with a capacitor of capacitance 50 μF, with π√x 200 V, 50 Hz AC source. The value of x will be _____ .

Q28.Sodium light of wavelengths 650 nm and 655 nm is used to study diffraction at a single slit of aperture 0. 5 mm. The distance between the slit and the screen is 2. 0 m. The separation between the positions of the first maxima of diffraction pattern obtained in the two cases is _____ ×10−5 m

Q28.A wire of length 314 cm carrying current of 14 A is bent to form a circle. The magnetic moment of the coil is A −m2 . [Given π = 3. 14]

Q28.A singly ionized magnesium atom (A = 24) ion is accelerated to kinetic energy 5 keV, and is projected perpendicularly into a magnetic field B of the magnitude 0. 5 T. The radius of path formed will be _____ cm.

Q29.A beam of monochromatic light is used to excite the electron in Li++ from the first orbit to the third orbit. The wavelength of monochromatic light is found to be x × 10−10 m. The value of x is _____ . [Given hc = 1242 eV nm]

Q29.A conducting circular loop is placed in X −Y plane in presence of magnetic field B = (3t3ˆj 3t2ˆk) in SI unit. If the radius of the loop is 1 m, the induced emf in the loop, at time, t = 2 s is nπ V. The value of n is _____ .

Q29.The total current supplied to the circuit as shown in figure by the 5 V battery is _____ A.

Q29.The stopping potential for photoelectrons emitted from a surface illuminated by light of wavelength 6630Å is 0. 42 V . If the threshold frequency is x × 1013 s, where x is (nearest integer): (Given, speed light = 3 × 108 m s−1 . Planck's constant = 6. 63 × 10−34 J s)

Q29.In a series LCR circuit, the inductance, capacitance and resistance are 𝐿= 100 mH, C = 100 𝜇Fand 𝑅= 10 Ω respectively. They are connected to an AC source of voltage 220 V and frequency of 50 Hz. The approximate value of current in the circuit will be _____ 𝐴.

Q29.Two lighter nuclei combine to form a comparatively heavier nucleus by the relation given below: 2𝑋+1 2𝑋=1 4𝑌2 The binding energies per nucleon 2𝑋1 and 4𝑌2 are 1 . 1MeV and 7 . 6MeV respectively. The energy released in this process is_____ MeV.

Q29.In the given circuit, the value of current IL will be _____ mA. (When RL = 1 kΩ)

Q29.A potential barrier of 0. 4 V exists across a p-n junction. An electron enters the junction from the n -side with a speed of 6. 0 × 105 m s−1 . The speed with which electron enters the p side will be x3 × 105 m s−1 , then the value of x is _____.: (Given mass of electron = 9 × 10−31 kg, charge on electron = 1. 6 × 10−19 C.)

Q29. x is the ratio of energies of photons produced due to transition of an electron of hydrogen atom from its x+4 (i) third permitted energy level to the second level and (ii) the highest permitted energy level to the second permitted level. The value of x will be

Q29.A deuteron and a proton moving with equal kinetic energy enter into to a uniform magnetic field at right angle to the field. If rd and rp are the radii of their circular paths respectively, then the ratio rd will be √x : 1 where rp x is _____ .

Q29.Two beams of light having intensities I and 4I interfere to produce a fringe pattern on a screen. The phase difference between the two beams are π and π at points A and B respectively. The difference between the 2 3 resultant intensities at the two points is xI . The value of x will be _____ .

Q29.As per the given circuit, the value of current through the battery will be _____ A. JEE Main 2022 (26 Jun Shift 1) JEE Main Previous Year Paper

Q29.When light of frequency twice the threshold frequency is incident on the metal plate, the maximum velocity of emitted electron is v1 . When the frequency of incident radiation is increased to five times the threshold value, the maximum velocity of emitted electron becomes v2 . If v2 = xv1 , the value of x will be _____ .

Q30.In a vernier callipers, each cm on the main scale is divided into 20 equal parts. If tenth vernier scale division coincides with nineth main scale division. Then the value of vernier constant will be _____ ×10−2 mm