Practice Questions

Q26.A cell, shunted by a 8 Ω resistance, is balanced across a potentiometer wire of length 3 m . The balancing length is 2 m when the cell is shunted by 4 Ω resistance. The value of internal resistance of the cell will be _____ Ω.

Q26.A potentiometer wire of length 300 cm is connected in series with a resistance 780 Ω and a standard cell of emf 4 V. A constant current flows through potentiometer wire. The length of the null point for cell of emf 20mV is found to be 60 cm. The resistance of the potentiometer wire is _____ Ω.

Q26.The current I flowing through the given circuit will be _____ A . JEE Main 2022 (29 Jul Shift 1) JEE Main Previous Year Paper

Q26.All resistances in figure are 1 Ω each. The value of current ' I ' is a5 A . The value of a is _____ .

Q27.Current measured by the ammeter (A) in the reported circuit when no current flows through 10Ω resistance, will be _____ A . JEE Main 2022 (28 Jun Shift 1) JEE Main Previous Year Paper

Q27.In a double slit experiment with monochromatic light, fringes are obtained on a screen placed at some distance from the plane of slits. If the screen is moved by 5 × 10−2 m towards the slits, the change in fringe width is 3 × 10−3 cm . If the distance between the slits is 1 mm , then the wavelength of the light will be____ nm .

Q27.The intensity of the light from a bulb incident on a surface is 0. 22 W m−2 . The amplitude of the magnetic field in this light-wave is _____ ×10−9 T (Given : Permittivity of vacuum ϵ0 = 8. 85 × 10−12 C2 N−1 m−2 , speed of light in vacuum c = 3 × 108 m s−1 )

Q27.The current density in a cylindrical wire of radius 4 mm is 4 × 106 A m−2 . The current through the outer portion of the wire between radial distances R and R is _____ π A. 2

Q27.Magnetic flux (in weber) in a closed circuit of resistance 20 Ω varies with time t(s) as ϕ = 8t2 −9t + 5. The magnitude of the induced current at t = 0. 25 s will be _____ mA .

Q27.An electrical bulb rated 220 V, 100 W , is connected in series with another bulb rated 220 V , 60 W . If the voltage across combination is 220 V , the power consumed by the 100 W bulb will be about _____ W.

Q27.In the given circuit, the magnitude of VL and VC are twice that of VR . Given that f = 50 Hz , the inductance of the coil is 1 mH . The value of K is _____ . Kπ JEE Main 2022 (28 Jun Shift 2) JEE Main Previous Year Paper

Q27.The effective current I in the given circuit at very high frequencies will be _____ A . JEE Main 2022 (26 Jul Shift 1) JEE Main Previous Year Paper

Q27.Two identical thin biconvex lenses of focal length 15 cm and refractive index 1. 5 are in contact with each other. The space between the lenses is filled with a liquid of refractive index 1. 25 . The focal length of the JEE Main 2022 (24 Jun Shift 1) JEE Main Previous Year Paper combination is _____ cm.

Q27.The equivalent capacitance between points 𝐴 and 𝐵 in below shown figure will be _____ 𝜇F.

Q27.In the given figure, the value of 𝑉0 will be _____ V.

Q27.As shown in the figure, a potentiometer wire of resistance 20 Ω and length 300 cm is connected with resistance box (R.B.) and a standard cell of emf 4 V. For a resistance '𝑅' of resistance box introduced into the circuit, the null point for a cell of 20 mV is found to be 60 cm. The value of '𝑅' is _____ Ω. 1

Q27.In a coil of resistance 8 Ω, the magnetic flux due to an external magnetic field varies with time as 𝜙= 2 - 𝑡2 39 . The value of total heat produced in the coil, till the flux becomes zero, will be _____ J. JEE Main 2022 (26 Jul Shift 2) JEE Main Previous Year Paper

Q27.A parallel plate capacitor with width 4 cm, length 8 cm and separation between the plates of 4 mm is connected to a battery of 20 V . A dielectric slab of dielectric constant 5 having length 1 cm, width 4 cm and thickness 4 mm is inserted between the plates of parallel plate capacitor. The electrostatic energy of this system will be _____ ϵ0 J. (Where ϵ0 is the permittivity of free space)

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

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.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.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.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 → +