Practice Questions

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.In the following circuit, the battery has an emf of 2 V and an internal resistance of 𝛺. The power 3 consumption in the entire circuit is ______ W.

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

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.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 .

Q26.A charge of 4. 0 μC is moving with a velocity of 4. 0 × 106 m s−1 along the positive y-axis under a magnetic field B of strength T. The force acting on the charge is xˆi N. The value of x is ______. (2ˆk)

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.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 =______.

Q27.To determine the resistance (R) of a wire, a circuit is designed below. The V −I characteristic curve for this circuit is plotted for the voltmeter and the ammeter readings as shown in figure. The value of R is ______ Ω.

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.A moving coil galvanometer has 100 turns and each turn has an area of 2 . 0 cm2 . The magnetic field produced by the magnet is 0 . 01 T and the deflection in the coil is 0 . 05 radian when a current of 10 mA is JEE Main 2024 (01 Feb Shift 2) JEE Main Previous Year Paper passed through it. The torsional constant of the suspension wire is 𝑥× 10-5 N - m / rad . The value of 𝑥 is ______ .

Q27.A horizontal straight wire 5 m long extending from east to west falling freely at right angle to horizontal component of earth's magnetic field 0. 60 × 10−4 Wb m−2 . The instantaneous value of emf induced in the wire when its velocity is 10 m s−1 is _______ ×10−3 V . JEE Main 2024 (29 Jan Shift 2) JEE Main Previous Year Paper

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.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.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 ceiling fan having 3 blades of length 80 cm each is rotating with an angular velocity of 1200 rpm. The magnetic field of earth in that region is 0. 5 G and angle of dip is 30°. The emf induced across the blades is Nπ × 10−5 V . The value of N is _______.

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.Two long, straight wires carry equal currents in opposite directions as shown in figure. The separation between the wires is 5. 0 cm. The magnitude of the magnetic field at a point P midway between the wires is _____ μT . (Given: μ0 = 4π × 10−7 T m A−1 )

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.A 2 A current carrying straight metal wire of resistance 1Ω, resistivity 2 × 10−6Ωm , area of cross-section 10 mm2 and mass 500 g is suspended horizontally in mid air by applying a uniform magnetic field →B . The magnitude of B is _____ ×10−1 T (given, g = 10 m/s2 ). JEE Main 2024 (05 Apr Shift 1) JEE Main Previous Year Paper

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.The magnetic field existing in a region is given by →B = 0.2(1 + 2x)^k T. A square loop of edge 50 cm carrying 0.5 A current is placed in x −y plane with its edges parallel to the x −y axes, as shown in figure. The magnitude of the net magnetic force experienced by the loop is_____ mN .

Q27.The coercivity of a magnet is 5 × 103 A/m . The amount of current required to be passed in a solenoid of length 30 cm and the number of turns 150 , so that the magnet gets demagnetised when inside the solenoid is _____A.

Q27.A square loop of edge length 2 m carrying current of 2 A is placed with its edges parallel to the x y axis. A magnetic field is passing through the x −y plane and expressed as →B = B0(1 + 4x)^k, where B0 = 5 T. The net magnetic force experienced by the loop is _______ N .

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