An electric current i enters and leaves a uniform circular wire of radius a through diametrically opposite points. A charge particle q moving along the axis of the circular wire passes tough its center at speed v. The magnetic force acting on the particle when it passes through the center has a magnitude.
Current is entering into the circular wire. According to right hand thumb rule the magnetic field will be in axis of the circular wire. It is given that the charge particle is moving along the axis of the wire.
Formula used: Magnetic force is given by the formula
Where F is magnetic force
q is electric charge =
v is velocity
B is magnetic filed
is angle between magnetic field and a charge
θ will be zero because the angle between the magnetic field and charge particle is 0° or 180°.
When the particle is moving along the axis of a wire the magnetic force acting on it will be zero. So option D is correct.