Practice Questions

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.Eight copper wire of length 𝑙 and diameter d are joined in parallel to form a single composite conductor of resistance 𝑅. If a single copper wire of length 2𝑙 have the same resistance 𝑅 then its diameter will be _____ 𝑑.

Q28.The frequencies at which the current amplitude in an LCR series circuit becomes times its maximum value, √2 are 212 rad s-1 and 232 rad s-1. The value of resistance in the circuit is 𝑅= 5 Ω. The self inductance in the circuit is _____ mH.

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.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.

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.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.A metallic rod of length 20 cm is placed in North-South direction and is moved at a constant speed of 20 m s−1 towards East. The horizontal component of the Earth's magnetic field at that place is 4 × 10−3 T and the angle of dip is 45°. The emf induced in the rod is _____ mV . JEE Main 2022 (27 Jun Shift 2) JEE Main Previous Year Paper

Q28.The length of a given cylindrical wire is increased to double of its original length. The percentage increase in the resistance of the wire will be _____ %

Q28.A convex lens of focal length 20 cm is placed in front of convex mirror with principal axis coinciding each other. The distance between the lens and mirror is 10 cm. A point object is placed on principal axis at a distance of 60 cm from the convex lens. The image formed by combination coincides the object itself. The focal length of the convex mirror is _____ cm.

Q28.The half life of a radioactive substance is 5 years. After x years a given sample of the radioactive substance gets reduced to 6. 25% of its initial value. 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.A small bulb is placed at the bottom of a tank containing water to a depth of √7 m. The refractive index of water is 4 . The area of the surface of water through which light from the bulb can emerge out is xπ m2 . The 3 value of x is _____ .

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.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.For the given circuit the current through battery of 6 V just after closing the switch ' S ' will be _____ A . ​

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.A resistor develops 300 J of thermal energy in 15 s, when a current of 2 A is passed through it. If the current increases to 3 A, the energy developed in 10 s is _____ J.

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 8V Zener diode along with a series resistance 𝑅 is connected across a 20 V supply (as shown in the figure). If the maximum Zener current is 25 mA, then the minimum value of 𝑅 will be _____ Ω.

Q29.The X −Y plane be taken as the boundary between two transparent media M1 and M2 . M1 in Z ≥0 has a refractive index of √2 and M2 with Z < 0 has a refractive index of √3. A ray of light travelling in M1 along → the direction given by the vector A = 4√3i −3√3j −5ˆk, is incident on the plane of separation. The value of difference between the angle of incident in M1 and the angle of refraction in M2 will be _____ degree.

Q29.An AC source is connected to an inductance of 100 mH , a capacitance of 100 μF and a resistance of 120 Ω as shown in figure. The time in which the resistance having a thermal capacity 2 J ∘C−1 will get heated by 16°C is _____ s.

Q29.An object ' O' is placed at a distance of 100 cm in front of a concave mirror of radius of curvature 200 cm as shown in the figure. The object starts moving towards the mirror at a speed 2 cm s−1 . The position of the image from the mirror after 10 s will be at _____ cm.