Practice Questions

Q26.The current density in a cylindrical wire of radius r = 4. 0 mm is 1. 0 × 106 A2 m2 . The current through the outer portion of the wire between radial distances r and r is xπ A ; where x is 2

Q26.For the network shown below, the value of VB −VA is _____ V . JEE Main 2022 (29 Jun Shift 1) JEE Main Previous Year Paper

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.When a gas filled in a closed vessel is heated by raising the temperature by 1°C, its pressure increases by 0 . 4% The initial temperature of the gas is _____ 𝐾. Q27.27 identical drops are charged at 22 V each. They combine to form a bigger drop. The potential of the bigger drop will be _____ V.

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.A meter bridge setup is shown in the figure. It is used to determine an unknown resistance R using a given resistor of 15 Ω. The galvanometer (G) shows null defection when tapping key is at 43 cm mark from end A . If the end correction for end A is 2 cm, then the determined value of R will be Ω.

Q26.The first overtone frequency of an open organ pipe is equal to the fundamental frequency of a closed organ pipe. If the length of the closed organ pipe is 20 cm. The length of the open organ pipe is _____ cm

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 circular coil of 1000 turns each with area 1 m2 is rotated about its vertical diameter at the rate of one revolution per second in a uniform horizontal magnetic field of 0. 07 T. The maximum voltage generation will be _____ V.

Q26.As show in the figure, in steady state, the charge stored in the capacitor is _____ ×10−6C.

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.Resistance are connected in a meter bridge circuit as shown in the figure. The balancing length l1 is 40 cm. Now an unknown resistance x is connected in series with P and new balancing length is found to be 80 cm measured from the same end. Then the value of x will be _____ Ω.

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

Q26.The volume charge density of a sphere of radius 6 m is 2 μC cm-3. The number of lines of force per unit surface area coming out from the surface of the sphere is _____ × 1010 N C-1 . [Given : Permittivity of vacuum 𝜖0 = 8 . 85 × 10-12C2 N-1 - m-2]

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.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 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.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 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.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.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.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 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