AIIMS Physics Moving Charges And Magnetism Class 12 Questions

A semi circular arc of radius r and a straight wire along the diameter, both are carrying same current i. Find out magnetic force per unit length on the small element P, which is at the centre of curvature.

A coil is placed in y-z plane making an angle of 30° with x-axis. The current through coil is I, and number of turns are N. If a magnetic field of strength ‘B’ is applied in positive x-direction, then find the torque experienced by the coil: (Radius of coil is R) (N = 100, I = 1 Å, R = 2m, B = 1/π T)

A current i flows through a circular loop as shown. Determine the magnetic field at the center of the loop.

Find force per unit length at P.

Find magnetic field at centre P if length of side of square loop is 20 cm.

In figure two parallel infinitely long current carrying wires are shown. If resultant magnetic field at A is zero, then determine current I₁.

Two circular loops having same radius $[R = 10 \text{ cm}]$ and same current $\frac{7}{2} \text{ A}$ are placed along same axis as shown. If distance between their centre is $10 \text{ cm}$, find net magnetic field at point P.

The unit of magnetic flux is Weber.

Force on current carrying loop (Radius = R) in uniform magnetic (B) field which is at an angle 30º with the normal will be :

The magnetic dipole moment is calculated as, M = i × πr² = (2e/2πr) × v × πr² = 2evr/2 = evr

In figure two parallel infinitely long current carrying wires are shown. If resultant magnetic field at point A is zero. Then determine current I.

The magnetic force on the charged particle is given by, F_B = qvBsinθ. As the particle is released from rest therefore, there may be no force on the particle and hence, it may remain stationary. As the force on the particle is zero therefore, magnetic field does no work on the particle. Hence, both assertion and reason are false.

Assertion: The kinetic energy does not change when a particle moves in uniform magnetic field. Reason: The velocity of the particle is not affected by magnetic field.

Assertion: Paramagnetic substances get poorly attracted in magnetic field.

At what distance for a long straight wire carrying a current of 12 Å will the magnetic field be equal to 3×10⁻⁵ Wb/m²?

Deuteron and an α particle move in same radius in a uniform magnetic ‘B’ field. If energy of deuteron is E₀ then find out the energy of α particle.

A long cylindrical wire carrying current of 10 amp. has radius of 5 mm, then find its magnetic field induction at a point 2 mm from the centre of the wire

2 long parallel wires which are 2 m apart carry current in the opposite direction but of same magnitude 2 amp, then find out the value of magnetic field intensity at the mid-point of the 2 wires and in the same plane.

‘Biot-Savart’ law of magnetism is analogous to:

Consider the figure shown below. The expression for magnetic field is given by, B = (μ₀I / 4πd) [sin ϕ₁ + sin ϕ₂] Now, ϕ₁ = ϕ₂ = ϕ So, B = (μ₀I / 2πd) [sin ϕ] From figure, sin ϕ = 1.5 / √3.25 Substitute 4π × 10⁻⁷ for μ₀, 1 cm for d in the above expression.

Consider the circular loop having current i and with central point O. The magnetic field at the central point is

The angle of dip if dip needle oscillating in vertical plane makes 40 oscillations per minute in a magnetic meridian and 30 oscillations per minute in vertical plane at right angle to the magnetic meridian is

In the following questions, a statement of assertion is given followed by a corresponding statement of reason. Assertion: The magnetic field at the end of very long current carrying solenoid is half of that at the center. Reason: The focal length of lens does not depends on color of light used.

The magnetic field at the centre O of the arc shown in the figure is

Consider the circular loop having current $i$ and with central point $O$. The magnetic field at the central point $O$ is

The variation of magnetic susceptibility with the temperature of a ferromagnetic material can be plotted as

Assertion (A) Above Curie temperature, a ferromagnetic material becomes paramagnetic. Reason (R) When a magnetic material is heated to very high temperature, it loses its magnetic properties.

Assertion (A) A wire bent into an irregular shape with the points P and Q fixed. If a current I passed through the wire, then the area enclosed by the irregular portion of the wire increases. Reason (R) Opposite currents carrying wires repel each other.

Assertion: Magnetic lines forms closed loops in nature. Reason: Mono-magnetic pole does not exist in nature.

Assertion: Magnetic field is useful in producing parallel beam of charged particle. Reason: Magnetic field inhibits the motion of charged particle moving across it.

A wire of mass 100 g, length 1 m and current 5 Å is balanced in mid air by a magnetic field B, then find the value of B.

A toroid with mean radius r₀ diameter 2a have N turns carrying current I. What is the magnetic field B inside the toroid?

Two wires carrying

Assertion: Magnetic force is always perpendicular to the magnetic field. Reason: Electric force is along the direction of electric field.

What is the dimensions of magnetic field B in terms of C (= coulomb), M, L, T?

A proton travels few distance in an electric field, then it enters a crossed magnetic field of 1 T and radius 0.2 m, Find the velocity of proton.

Magnetic field at a distance a from long current carrying wire is proportional to

When a positively charged particle enters into a uniform magnetic field with uniform velocity, its trajectory can be (i) a straight line (ii) a circle (iii) a helix

An uncharged particle is moving with a velocity of v in non-uniform magnetic field as shown. Velocity v would be

Assertion: If a proton and an α-particle enter a uniform magnetic field perpendicularly with the same speed, the time period of revolution of α-particle is double that of proton. Reason: In a magnetic field, the period of revolution of a charged particle is directly proportional to the mass of the particle and is inversely proportional to charge of particle.

A current I₁ carrying wire AB is placed near another long wire CD carrying current I₂. If wire AB is free to move, it will have

Assertion : A charge, whether stationary or in motion produces a magnetic field around it. Reason : Moving charges produce only electric field in the surrounding space.

Assertion: We cannot think of magnetic field configuration with three poles. Reason: A bar magnet does exert a torque on itself due to its own field.

Assertion: When radius of circular loop carrying current is doubled, its magnetic moment becomes four times. Reason: Magnetic moment depends on area of the loop.

Assertion: The energy of charged particle moving in a uniform magnetic field does not change. Reason: Work done by magnetic field on the charge is zero.

What is the magnetic field at a distance R from a coil of radius r carrying current I?

Circular loop of a wire and a long straight wire carry currents Iₗ and Iₛ respectively as shown in figure. Assuming that these are placed in the same plane, the magnetic fields will be zero at the centre of the loop when separation H is

A proton and an α-particle, moving with the same velocity, enter into a uniform magnetic field, acting normal to the plane of their motion. The ratio of the radii of the circular paths described by the proton and α-particle is

A circular coil of radius R carries an electric current. The magnetic field due to the coil at a point on the axis of the coil located at a distance r from the center of the coil, such that r >> R, varies as

The magnetic field due to a straight conductor of uniform cross-section of radius a and carrying a steady current is represented by