Test: Moving Charges and Magnetism - 1 - CUET Humanities MCQ

Magnetic field around the straight current carrying wire is given by:

The shape of a magnet does not affect its magnetism. Magnetism is highest at the poles of a magnet and it is not determined by its shape.

If the electric field is switched off and the same magnetic field is maintained, the electrons will move in a circular orbit as the force due to the magnetic field is always perpendicular to the velocity vector and the direction of the magnetic field.

A charged particle is undergoing circular motion in a magnetic field. The time period is independent of the speed and the radius of the orbit as

At the neutral point, the magnetic field produced by the magnet becomes equal and opposite to some other magnetic field. This other magnetic field is actually the horizontal component of earth's magnetic field. 
Magnetic field at the centre of circular coil  I and r being the current and radius of circular coil respectively.
or

The time period of the revolution in the magnetic field,

Mass of the alpha particle = 4 times the mass of the proton Charge on the alpha particle = 2 times the charge on the proton

A wire PQR is bent as shown in the figure and is placed in a region of a uniform magnetic field B. The length of PQ = length of QR = L. A current l ampere flows through the wire as shown. The magnitude of the force on PQ will be zero as the angle between the magnetic field and the current = 0.

Angle between the magnetic field and QR is 90°, so the force on QR,

When we bring the same poles of two magnets near to each other, they repel each other.
A permanent magnet causes repulsion with one pole when the poles are brought (in turns) near a suspended magnet. An unmagnetised magnet material would be attracted to both the poles.
So, repulsion is the sure test of magnetism.