Question

Two parallel circular current carrying loops each of radius R are placed coaxially. The centres of loops are a distance R apart. Each coil carries a steady current/ in the same direction The magnetic filed at midpoint between the separation is

• A. $\frac{4{\mu }_{0}l}{5\sqrt{5}R}$
• B. $\frac{{\mu }_{0}l}{5\sqrt{5}R}$
• C. zero
• D. $\frac{{B\mu }_{0}l}{5\sqrt{5}R}$

Answer 1

Answer: (C)

zero

Given

Two circular coils placed coaxially of radius R

They are apart by R distance

Solution

As both circular coils have same radius and same current therefore both coils will make same magnetic field on axial point of $\int dbsin\theta$

and direction is away from centre..

Because of this magnetic field will cancel out.

The correct option is C