Practice Questions

Q26.As shown in the figure an inductor of inductance 200 mH is connected to an AC source of emf 220 V and frequency 50 Hz. The instantaneous voltage of the source is 0 V when the peak value of current is √aπ A . The value of a is _____ .

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 long cylindrical volume contains a uniformly distributed charge of density ρ C m−3 . The electric field inside the cylindrical volume at a distance x = 2ε0ρ m from its axis is _____ V m−1 . JEE Main 2022 (27 Jul Shift 1) 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.A 110 V, 50 Hz, AC source is connected in the circuit (as shown in figure). The current through the resistance 55 Ω, at resonance in the circuit, will be _____ A.

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.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.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.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)

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.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.In the given circuit 'a' is an arbitrary constant. The value of m for which the equivalent circuit resistance is minimum, will be √x2 . The value of x is _____ .

Q27.A capacitor of capacitance 500 𝜇F is charged completely using a de supply of 100 V. It is now connected to an inductor of inductance 50 mH to form an LC circuit. The maximum current in LC circuit will be _____ A.

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

Q27.A closely wounded circular coil of radius 5 cm produces a magnetic field of 37. 68 × 10−4 T at its center. The current through the coil is _____ A . [Given, number of turns in the coil is 100 and π = 3. 14]

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

Q27.A ray of light is incident at an angle of incidence 60° on the glass slab of refractive index √3. After refraction, the light ray emerges out from other parallel faces and lateral shift between incident ray and emergent ray is 4√3 cm . The thickness of the glass slab is _____ cm .

Q27.In meter bridge experiment for measuring unknown resistance ' S ', the null point is obtained at a distance 30 cm from the left side as shown at point D. If R is 5. 6 kΩ, then the value of unknown resistance ' S ' will be _____ Ω.

Q27.Two 10 cm long, straight wires, each carrying a current of 5 A are kept parallel to each other. If each wire experienced a force of 10−5 N , then separation between the wires is _____ cm.

Q28.In a Young's double slit experiment, an angular width of the fringe is 0. 35° on a screen placed at 2 m away for particular wavelength of 450 nm . The angular width of the fringe, when whole system is immersed in a medium of refractive index 7 , is 1 . The value of α is _____ . α 5