Practice Questions

Q26.Two charges of -4 μC and +4 μC are placed at the points 𝐴( 1, 0, 4 ) m and 𝐵( 2, - 1, 5 ) m located in an electric field →𝐸= 0 . 20 ^i V cm-1. The magnitude of the torque acting on the dipole is 8√𝛼× 10-5 N m, where 𝛼= _________.

Q26.A 16 Ω wire is bend to form a square loop. A 9 V battery with internal resistance 1 Ω is connected across one of its sides. If a 4 μF capacitor is connected across one of its diagonals, the energy stored by the capacitor will be x 2 μJ, where x =______.

Q26.In the experiment to determine the galvanometer resistance by half-deflection method, the plot of 1/θ vs the resistance (R) of the resistance box is shown in the figure. The figure of merit of the galvanometer is _____ ×10−1 A/ division. [The source has emf 2V]

Q26.An electric field →E = (2x^i)NC −1 exists in space. A cube of side 2 m is placed in the space as per figure given below. The electric flux through the cube is ______ Nm2/C. JEE Main 2024 (09 Apr Shift 2) JEE Main Previous Year Paper

Q26.The current flowing through the 1Ω resistor is 10n A. The value of n is _________

Q26.Two wires A and B are made up of the same material and have the same mass. Wire A has radius of 2.0 mm and wire B has radius of 4.0 mm. The resistance of wire B is 2Ω. The resistance of wire A is _____ Ω. JEE Main 2024 (04 Apr Shift 2) JEE Main Previous Year Paper

Q26.A wire of resistance 20Ω is divided into 10 equal parts, resulting pairs. A combination of two parts are connected in parallel and so on. Now resulting pairs of parallel combination are connected in series. The equivalent resistance of final combination is _____ Ω.

Q26.The charge accumulated on the capacitor connected in the following circuit is ______ μC. (Given C = 150 μF)

Q26.Equivalent resistance of the following network is ________ 𝛺.

Q26.In an electrical circuit drawn below the amount of charge stored in the capacitor is _______ μC .

Q26.Resistance of a wire at 0∘C, 100∘C and t∘C is found to be 10Ω, 10.2Ω and 10.95Ω respectively. The temperature t in Kelvin scale is _________

Q26.A wire of resistance R and radius r is stretched till its radius became r/2. If new resistance of the stretched wire is xR, then value of x is _______ →

Q26.In the given figure an ammeter A consists of a 240Ω coil connected in parallel to a 10Ω shunt. The reading of the ammeter is mA

Q26.Two cells are connected in opposition as shown. Cell E1 is of 8 V emf and 2 Ω internal resistance; the cell E2 is of 2 V emf and 4 Ω internal resistance. The terminal potential difference of cell E2 is ______ V .

Q27.The magnetic potential due to a magnetic dipole at a point on its axis situated at a distance of 20 cm from its center is 1. 5 × 10−5 T m . The magnetic moment of the dipole is _______ A m2 . (Given : μ0 = 10−7 T m A−1 ) 4π

Q27.A circular coil having 200 turns, 2.5 × 10−4 m2 area and carrying 100μA current→ is placed in a uniform magnetic field of 1T. Initially the magnetic dipole moment (M) was directed along →B. Amount of work, required to rotate the coil through 90∘ from its initial orientation such that M becomes perpendicular to →B, is ______ μJ.

Q27.A regular polygon of 6 sides is formed by bending a wire of length 4 π meter. If an electric current of 4𝜋√3 A is flowing through the sides of the polygon, the magnetic field at the centre of the polygon would be 𝑥× 10-7 T . The value of 𝑥 is ______.

Q27.Two resistance of 100𝛺 and 200𝛺 are connected in series with a battery of 4 V and negligible internal resistance. A voltmeter is used to measure voltage across 100𝛺 resistance, which gives reading as 1 V. The resistance of voltmeter must be _______ 𝛺. JEE Main 2024 (30 Jan Shift 2) JEE Main Previous Year Paper

Q27.Two parallel long current carrying wire separated by a distance 2r are shown in the figure. The ratio of magnetic field at A to the magnetic field produced at C is x . The value of x is _____ 7

Q27.An electron moves through a uniform magnetic field →𝐵= 𝐵0 ^i + 2𝐵0 ^j T. At a particular instant of time, the → velocity of electron is →𝑢= 3 ^i + 5 ^j m s-1. If the magnetic force acting on electron is 𝐹= 5𝑒 ^k N, where 𝑒 is the charge of electron, then the value of 𝐵0 is ____ T.

Q27.An electron with kinetic energy 5eV enters a region of uniform magnetic field of 3 μT perpendicular to its direction. An electric field E is applied perpendicular to the direction of velocity and magnetic field. The value of E , so that electron moves along the same path, is _______ NC−1 . ( Given, mass of electron = 9 × 10−31 kg , electric charge = 1.6 × 10−19C)

Q27.A coil having 100 turns, area of 5 × 10−3 m2 , carrying current of 1 mA is placed in uniform magnetic field of 0.20 T such a way that plane of coil is perpendicular to the magnetic field. The work done in turning the coil through 90∘ is _______ μJ.

Q27.The magnetic field at the centre of a wire loop formed by two semicircular wires of radii 𝑅1 = 2𝜋 m and 𝑅2 = 4𝜋 m carrying current 𝐼= 4 A as per figure given below is 𝛼× 10-7 T. The value of 𝛼 is _____. (Centre O is common for all segments) JEE Main 2024 (27 Jan Shift 2) JEE Main Previous Year Paper

Q27.Two circular coils 𝑃 and 𝑄 of 100 turns each have same radius of 𝜋 cm. The currents in 𝑃 and 𝑅 are 1 A and 2 A respectively. 𝑃 and 𝑄 are placed with their planes mutually perpendicular with their centers coincide. The resultant magnetic field induction at the center of the coils is √𝑥 mT, where 𝑥= ______. [Use 𝜇0 = 4𝜋× 10−7 T m A−1]

Q27.A solenoid of length 0.5 m has a radius of 1 cm and is made up of ' m ' number of turns. It carries a current of 5 A . If the magnitude of the magnetic field inside the solenoid is 6.28 × 10−3 T then the value of m is _____.