Moving Charges And Magnetism - Electromagnetism - Physics Previous Year Questions

Two straight wires each \(10 \mathrm{~cm}\) long are parallel to one another and separated by \(2 \mathrm{~cm}\). When the current flowing in them is \(30 \mathrm{~A}\) and \(40 \mathrm{~A}\) respectively, the force experienced by either of the wires is

A long straight wire is carrying a current of \(12 \mathrm{~A}\). The magnetic field at a distance of \(8 \mathrm{~cm}\) is \(\left(\mu_0=4 \pi \times 10^{-7} \mathrm{~N} / \mathrm{A}^2\right)\)

The magnetic field at a point on the axis of a long solenoid having 5 turns per \(\mathrm{cm}\) length when a current of \(0.8 \mathrm{~A}\) flows through it is

A stream of electrons is projected horizontally to the right. A straight conductor carrying, a current is supported parallel to the electron stream and above it. If the current in the conductor is from left to right, what will be the effect on the electron stream?

Which of the following is deflected by the magnetic field?

A coil of 100 turns and area \(2 \times 10^{-2} \mathrm{~m}^2\) is pivoted about a vertical diameter in a uniform magnetic field and carries a current of \(5 \mathrm{~A}\). When the coil is held with its plane in North-South direction, it experiences a couple of \(0.33 \mathrm{~N}-\mathrm{m}\). When the plane is East-West, the corresponding couple is \(0.4 \mathrm{~N}-\mathrm{m}\). The value of magnetic induction is [Neglect earth's magnetic field]

In a cathode ray tube, a potential difference of 3000 volts is maintained between the deflector plates whose separation is \(2 \mathrm{~cm}\). A magnetic field of \(2.5 \times 10^{-3} \mathrm{~Wb} / \mathrm{m}^2\) at right angles to electric field gives no deflection of the electron beam, which received an initial acceleration by a potential difference of \(10000 \mathrm{~V}\). Calculate \((\mathrm{e} / \mathrm{m})\) of an electron.

Two parallel conductors carry current in opposite directions as shown in the figure. One conductor carries a current of \(20 \mathrm{~A}\). Point \(C\) is a distance \(d / 2\) to the right of a 20 A current. If \(d=18 \mathrm{~cm}\) and \(i\) is adjusted so that the magnetic field at \(C\) is zero, the value of the current \(i\) is

Two long parallel wires carry equal current \(i\) flowing in the same directions are at a distance \(4 d\) apart. The magnetic field \(B\) at a point \(P\) lying on the perpendicular line joining the wires and at a distance \(x\) from the mid-point is

A solenoid of length 0.4 m and having 500 turns of wire carries a current of 3 A . A thin coil having 10 , turns of wire and of radius 0.01 m carries a current of 0.4 A . The torque required to hold the coil in the middle of the solenoid with its axis perpendicular to the axis of solenoid.

A current carrying conductor experiences maximum force in magnetic field when the angle between current element and direction of magnetic field is

Which of the following graph represents the variation of magnetic flux density $B$ with distance $r$ for a straight long wire carrying an electric current?