A charged particle moves in a clockwise direction in a magnetic field which is perpendicular to plane of paper directed downwards. What is the nature of charged particle?

In the presence of magnetic field, the force on a charged particle is given as:

F = q× v× B

Where, q is the charge of the particle

V is the velocity of the particle

B is the magnetic field.

Now, the direction of charged particle is clock wise.

And, the magnetic field is inwards (perpendicular to the plane of paper in downwards direction)

We apply Flemings left hand rule to find the direction for any charge:

The thumb represents the force acting or direction of motion.

The fore finger represents the direction of magnetic field.

The central finger represents the direction of propagation of the charge.

And for negative charges (i.e. electrons) that the final force direction should be taken the opposite of what Flemings rule.

Therefore, here the charge is negative i.e. the particle is an electron.

Therefore, the diagram is given below: