Moving Charges And Magnetism - Electromagnetism - Physics Previous Year Questions

A current of 4 A is passed through a square loop of side 5 cm made of a uniform manganin wire as shown in the figure. The magnetic field at the centre of the loop is

Two identical wires, carrying equal currents are bent into circular coils $A$ and $B$ with 2 and 3 turns respectively. The ratio of the magnetic fields at the centres of the coils $A$ and $B$ is

A proton and an alpha particle moving with equal speeds enter normally into a uniform magnetic field. The ratio of times taken by the proton and the alpha particle to make one complete revolution in the magnetic field is

A solenoid of length 50 cm and radius 10 cm has two closely wound layers of windings 100 turns each. If a current of 2.5 A is passing through the windings, the magnetic field (in $10^{-4} \mathrm{~T}$ ) at a point 5 cm from the axis is

A solenoid of 1000 turns per metre has a core of material with relative permeability 400 . The windings of the solenoid are insulated from the core and a current of 2 A is passed through the solenoid. Then, the value of the magnetic intensity inside the solenoid is

An alpha particle moving with certain speed towards east enters a uniform magnetic field directed vertically up. The alpha particle will then move in

A square coil of side 10 cm having 200 turns is placed in a uniform magnetic field of 2 T such that the plane of the coil is in the direction of magnetic field. If the current through the coil is 3 mA , then the torque acting on the coil is

The magnetic field due to a current carrying circular coil on its axis at a distance of $\sqrt{2} \mathrm{~d}$ from the centre of the coil is $B$. If $d$ is the diameter of the coil, then the magnetic field at the centre of the coil is

A proton moving with a velocity of $8 \times 10^5 \mathrm{~ms}^{-1}$ enters a uniform magnetic fleld normal to the direction of the magnetic field. If the radius of the circular path of the proton in the magnetic field is 8.3 cm , then the magnitude of the magnetic field is

(Charge of proton $=1.6 \times 10^{-19} \mathrm{C}$ and mass of the proton $=1.66 \times 10^{-27} \mathrm{~kg}$ )

As shown in the figure, a uniform straight wire of length $30 \sqrt{3} \mathrm{~cm}$ is bent in the form of an equilateral triangle $A B C$. A uniform magnetic field $2 T$ is applied parallel to the side $B C$. If the current through the wire is 2 A , the magnitude of the force on the side $A C$ is ( $\bar{B}$ represents the direction of the magnetic field)

The number of turns of two circular coils $A$ and $B$ are 300 and 200 respectively. The magnetic moments of the two coils $A$ and $B$ are in the ratio $1: 2$. If the two coils carry equal currents, then the ratio of radii of coils $A$ and $B$ is