Moving Charges and Magnetism

CBSE Class 12 Physics · 124 board questions from this chapter; 122 listed below, 2023–2026

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Two particles of masses m_1 and m_2 having charges q_1 and q_2 respectively are projected with the same velocity in a region of…2026
A long straight wire of circular cross-section (radius a) carries a steady current I. The current is uniformly distributed across…2026
An electron moves around the nucleus in a circular orbit of radius r and makes n revolutions per second. The value of equivalent…2026
Four long straight thin wires are held vertically at the corners A, B, C and D of a square of side 'a', kept on a table and carry…2026
A charged particle is moving in a uniform magnetic field B with a constant speed v in a circular path of radius r. Which of the…2026
A straight long wire lying along y-axis, carries a current of 1 A along -y direction. The magnetic field due to the conductor at…2026
A person is standing facing geographic north and a vertical wire in front of him is carrying a current in downward direction. The…2026
A galvanometer of resistance 27 Ω is converted into an ammeter of range ( 0-10 mA ) using a resistance of 3 Ω. The galvanometer…2026
A coil having 100 closely wound turns and area of cross-section 300 mm^2 carries a current of 5 mA. The magnitude of the magnetic…2026
A charged particle of mass m having kinetic energy K passes undeflected through a region with electric field E and magnetic field…2026
A straight conductor lies along x -axis and carries a current of 2 A along +x direction. The magnetic field at a point (0, 40 cm,…2026
A straight conductor lies along x -axis. It carries a current of 10 A along +x direction. The magnetic field B due to 1 cm…2026
A circular loop has radius R and carries current I as shown in figure. In order that the net magnetic field at the centre of the…2026
A galvanometer of resistance G is converted into a voltmeter of range ( 0-V ) by connecting a resistor of 250 Ω with it. If…2026
Assertion: The cylindrical soft iron core in a moving coil galvanometer only makes the magnetic field radial and does not affect…2026
A wire of length L is bent round into (i) a square coil having N turns and (ii) a circular coil having N turns. The coil in both…2026
Figure shows a narrow beam of electrons entering with a velocity of 3 × 10^7 m / s, symmetrically through the space between two…2026
A circular coil of 30 turns and radius 8.0 cm carrying a current of 6 A is suspended vertically in a uniform horizontal magnetic…2026
Write the expression for the magnetic field due to a current element in vector form. Consider a 1 cm segment of a wire, centered…2026
The figure given below shows three straight long parallel conductors (1), (2) and (3) kept in x-y plane, carrying currents 2I, I…2026
Derive an expression for the magnetic field B, due to a circular coil of N turns, each of radius r carrying current I, at a…2026
A galvanometer is used to detect or/and measure small currents in an electrical circuit. It essentially works on the fact that a…2026
A charged particle +q in an electric field E experiences a force in the direction of the electric field. As a result, its kinetic…2026
(i) A rectangular loop of sides a and b carrying current I is placed in a magnetic field B such that its area vector A makes an…2026
A 1 cm straight segment of a conductor carrying 1 A current in x direction lies symmetrically at origin of Cartesian coordinate…2025
A straight conductor is carrying a current of 2 A in +x direction along it. A uniform magnetic field B=(0.6 j+0.8 k) T is…2025
A particle of mass m and charge q moving with velocity v i is subjected to a uniform electric field E j. The particle will…2025
A particle having charge +q enters a uniform magnetic field B as shown in the figure. The particle will describe:2025
A 1 cm segment of a wire lying along x -axis carries current of 0.5 A along +x direction. A magnetic field B=(0.4 mT) j+(0.6 mT)…2025
In a circular loop of radius R, current I enters at point A and exits at point B, as shown in the figure. The value of the…2025
A particle of mass m and charge q moves along y -axis in a region in which a uniform magnetic field B is pointing along x -axis.…2025
The value of magnetic field at point O in the given figure is:2025
A particle with charge q moving with velocity v=v_0 i enters a region with magnetic field B=B_1 j+B_2 k. The magnitude of force…2025
A bar magnet is initially at right angles to a uniform magnetic field. The magnet is rotated till the torque acting on it becomes…2025
A charged particle gains a speed of 10^6 ms^-1, when accelerated from rest through a potential difference 10 kV. It enters a…2025
A current of (10/(π)) A is maintained in a circular loop of radius 14 cm. The value of dipole moment associated with the loop is:2025
A galvanometer can be converted into an ammeter of desired range by connecting a:2025
A proton and an α -particle enter with the same velocity v in a uniform magnetic field B such that v ⊥ B. The ratio of the radii…2025
A long straight wire is held vertically and carries a steady current in upward direction. The shape of magnetic field lines…2025
Assertion: A charged particle is moving with velocity v in x-y plane, making an angle θ(0<θ<(π)/2) with x -axis. If a uniform…2025
Assertion: The deflection in a galvanometer is directly proportional to the current passing through it. Reason (R): The coil of a…2025
A current of 5 A is passing along +X direction through a wire lying along X -axis. Find the magnetic field B at a point r=(3 i+4…2025
A circular coil of wire having 200 turns, each of radius 4.0 cm is placed in a horizontal plane. It carries a current of 0 · 40 A…2025
A particle of charge q is moving with a velocity v at a distance ' d ' from a long straight wire carrying a current ' I ' as…2025
In a region of a uniform electric field E, a negatively charged particle is moving with a constant velocity v=-v_0 i near a long…2025
Using Biot-Savart law, derive expression for the magnetic field ( B ) due to a circular current carrying loop at a point on its…2025
A charged particle q moving with a velocity v is subjected to a uniform magnetic field B acting perpendicular to v. If a uniform…2025
In which cases does a charged particle not experience a force in a magnetic field? A square loop MNPK of side ' l ' carrying a…2025
(i) Write Biot-Savart's law in vector form. (ii) Two identical circular coils A and B, each of radius R, carrying currents I and…2025
Write vector form of Biot-Savart law. Two insulated long straight wires, each carrying 2 · 0 A current are kept along xx^′ and…2025
Define magnetic moment of a current-carrying coil. Write its SI unit. A coil of 60 turns and area 1.5 × 10^-3 m^3 carrying 2A…2025
A rectangular loop carries a current of 1 A. A straight long wire carrying 2 A current is kept near the loop in the same plane as…2025
An electron of mass m and charge - e is revolving anticlockwise around the nucleus of an atom. Obtain the expression for the…2025
Use Ampere's law to derive the expression for the magnetic field due to a long straight current carrying wire of infinite length.…2025
A galvanometer is an instrument used to show the direction and strength of the current passing through it. In a galvanometer, a…2025
(i) With the help of a labelled diagram, explain the principle of working of a moving coil galvanometer. Write the purpose of…2025
(i) What is the source of force acting on a current-carrying conductor placed in a magnetic field? Obtain the expression for…2025
(i) A proton moving with velocity V in a non-uniform magnetic field traces a path as shown in the figure. The path followed by…2025
A particle of mass m and charge q describes a circular path of radius R in a magnetic field. If its mass and charge were 2 m and…2024
Two insulated concentric coils, each of radius R, placed at right angles to each other, carry currents I and √3 I respectively.…2024
A 2.0 cm segment of wire, carrying 5.0 A current in positive y-direction lies along y -axis, as shown in the figure. The magnetic…2024
A wire of length 4 · 4 m is bent round in the shape of a circular loop and carries a current of 1.0 A. The magnetic moment of the…2024
A piece of wire bent in the form of a circular loop A carries a current I. The wire is then bent into a circular loop B of two…2024
Two charged particles, P and Q, each having charge q but of masses m_1 and m_2, are accelerated through the same potential…2024
Two thin long parallel wires separated by a distance 'a' carry current ' I ' in opposite directions. The wires will:2024
A loop carrying a current I clockwise is placed in x-y plane, in a uniform magnetic field directed along z -axis. The tendency of…2024
A circular loop of wire, carrying a current ' I ' is lying in xy -plane with its centre coinciding with the origin. It is…2024
A galvanometer of resistance 50 Ω is converted into a voltmeter of range (0-2 V) using a resistor of 1.0 k Ω. If it is to be…2024
A galvanometer of resistance 100 Ω gives full scale deflection for a current of 1.0 mA. It is converted into an ammeter of range…2024
A galvanometer shows full scale deflection for a current I_g. If a shunt of resistance S_1 is connected to the galvanometer, it…2024
A current carrying circular loop of magnetic moment M is suspended in a vertical plane in an external magnetic field B such that…2024
A 10 cm long wire lies along y -axis. It carries a current of 1.0 A in positive y-direction. A magnetic field B=(5 mT) j-(8 mT) k…2024
A straight wire is kept horizontally along east-west direction. If a steady current flows in wire from east to west, the magnetic…2024
Two long straight parallel conductors A and B, kept at a distance r, carry current I in opposite directions. A third identical…2024
A particle of mass m and charge q is moving with velocity v=v_x i+v_y j. If it is subjected to a magnetic field B=B_0 i, it will…2024
A galvanometer of resistance G Ω is converted into an ammeter of range 0 to IA. If the current through the galvanometer is 0.1 %…2024
A galvanometer of resistance 100 Ω is converted into an ammeter of range ( 0-1 A ) using a resistance of 0.1 Ω. The ammeter will…2024
A circular loop A of radius R carries a current I. Another circular loop B of radius r(=R/20) is placed concentrically in the…2024
Assertion: The energy of a charged particle moving in a magnetic field does not change. Reason (R): It is because the work done…2024
Assertion: A proton and an electron enter a uniform magnetic field B with the same momentum p such that p is perpendicular to B.…2024
Assertion: Two long parallel wires, freely suspended and connected in series to a battery, move apart. Reason (R): Two wires…2024
Assertion: An electron and a proton enter with the same momentum p in a magnetic field B such that p ⊥ B. Then both describe a…2024
Derive an expression for magnetic force F acting on a straight conductor of length L carrying current I in an external magnetic…2024
An electron (charge - e, mass m ) is revolving around a nucleus, in a hydrogen atom, in a circle of radius r. Derive an…2024
Two long straight parallel conductors carrying currents, exert a force on each other. Why? Derive an expression for the force per…2024
A rectangular loop of area A, carrying current I, is placed in a uniform magnetic field B. With the help of a suitable diagram,…2024
A circular coil with cross-sectional area 0.2 cm^2 carries a current of 4 A. It is kept in a uniform magnetic field of magnitude…2024
A proton with kinetic energy 1.3384 × 10^-14 J moving horizontally from north to south, enters a uniform magnetic field B of 2 ·…2024
Two long, straight, parallel conductors carry steady currents in opposite directions. Explain the nature of the force of…2024
Two long insulated straight wires carrying currents of 3 A and 5 A are arranged in XY plane as shown in figure. Find the…2024
An electron moving with a velocity v=(1.0 × 10^7 m / s) i+(0.5 × 10^7 m / s) j enters a region of uniform magnetic field B=(0.5…2024
A circular loop of radius 10 cm carrying current of 1.0 A lies in x-y plane. A long straight wire lies in the same plane parallel…2024
An infinite straight conductor is kept along X^′ X axis and carries a current I. A charge q at point P(0, r) starts moving with…2024
An electron is moving with a velocity v=(3 × 10^6 m/s) i. It enters a region of magnetic field B=(91 mT) k. Calculate the…2024
(i) A particle of mass m and charge q is moving with a velocity v in a magnetic field B as shown in the figure. Show that it…2024
An electron enters a uniform magnetic field with speed v. It describes a semicircular path and comes out of the field. The final…2023
Two thin long parallel wires A and B are separated by a distance r and carry current I each in the same direction. The force per…2023
A particle of mass m and charge -q is moving with a uniform speed v in a circle of radius r, with another charge q at the centre…2023
Beams of electrons and protons move parallel to each other in the same direction. They2023
A particle of mass m and charge q moving with a uniform velocity v=v_0 x i+v_0 y j enters a region with a magnetic field B=B_0 j.…2023
A long straight wire of radius 'a' carries a steady current ' I '. The current is uniformly distributed across its area of…2023
In a moving coil galvanometer, the deflecting torque τ acting on the coil is related to the current I flowing through it as:2023
Which of the following graphs correctly represents the variation of the magnitude of the magnetic field outside a straight…2023
Assertion: When radius of a circular loop carrying a steady current is doubled, its magnetic moment becomes four times. Reason (…2023
Assertion: A current carrying square loop made of a wire of length L is placed in a magnetic field. It experiences a torque which…2023
Assertion: The deflecting torque acting on a current carrying loop is zero when its plane is perpendicular to the direction of…2023
Briefly explain why and how a galvanometer is converted into an ammeter.2023
An alpha particle is projected with velocity v=(3 · 0 × 10^5 m / s) i into a region in which magnetic field B=[(0 · 4 T) i+(0 · 3…2023
A wire of length l is in the form of a circular loop A of one turn. This loop is reshaped into loop B of three turns. Find the…2023
A wire of length L is bent round in the form of (i) a square, and then (ii) an equilateral triangle. If current I is passed…2023
A particle of charge q and mass m starts moving with uniform velocity v_0 i. Specify the direction of magnetic field which should…2023
Write the expression for the Lorentz force on a particle of charge q moving with a velocity v in a magnetic field B. When is the…2023
Two identical circular loops P and Q, each of radius R carrying current I are kept in perpendicular planes such that they have a…2023
Two wires of equal lengths are shaped in the form of a square loop and a circular loop. Both loops are suspended in a uniform…2023
Write the expression for the Lorentz force on a particle of charge q moving with a velocity v in a magnetic field B. When is the…2023
Two circular loops A and B, each of radius 3 m, are placed coaxially at a distance of 4 m. They carry currents of 3 A and 2 A in…2023
A current carrying circular loop and a straight wire bent partly in the form of a semicircle are placed as shown in the figure.…2023
Briefly describe how the current sensitivity of a moving coil galvanometer can be increased. A galvanometer shows full scale…2023
Two infinitely long parallel conductors A and B, separated by 2 cm, carry 6 A and 2 A currents in opposite directions…2023
(i) Write the principle and explain the working of a moving coil galvanometer. A galvanometer as such cannot be used to measure…2023
(i) State Biot-Savart's law for the magnetic field due to a current carrying element. Use this law to obtain an expression for…2023
A beam of electrons moving horizontally with a velocity of 3 × 10^7 m / s enters a region between two plates as shown in the…2023

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