Question

A magnetic field is acting perpendicularly into the plane of paper shown in the diagram. A charged particle q entered in to the magnetic field with speed v at angles to the direction of magnetic field then

• A. The direction of magnetic force resulted on the charge q is in the upward direction along the plane of the paper.
• B. the magnitude of magnetic force resulted is F=qvB
• C. the work done by the magnetic force on the charged particle is zero'.
• D. None of the above

Answer 1

Answer: (A)

The direction of magnetic force resulted on the charge q is in the upward direction along the plane of the paper.

Given : $\text{q, v and uniform B}$

Solution :

We know that $\overrightarrow{F}=q(\overrightarrow{v}\times \overrightarrow{B})$

So, Using right hand thumb rule,

Place your right hand towards velocity and curl it inwards (because magnetic field is into the page). Notice that your thumb points upwards.

Hence, The direction of magnetic force resulted on the charge q is in the upward direction along the plane of the paper.

The Correct Opt : {A}