Question

An electric current ?I? enters and leaves a uniform circular wire of radius r through dfiametrically opposite points. A particle carrying a charge q moves along the axis of the circular wire with speed v. What is the magnetic force experienced by the particle when it passes through the centre of the circle ?

• A. $qv\frac{\mu_{0}i}{a}$
• B. $qv\frac{\mu_{0}i}{2a}$
• C. $qv\frac{\mu_{0}i}{2\pi a}$
• D. Zero

Answer 1

Answer: (D)

Zero

Answer 2

$Net magnetic fieldat centre = 0$
$\vec{F}=q\vec{V}\times\vec{B}=0$