Question

Two circular loops having same radius [R = 10 cm] and same current $\frac{7}{4}$ Aare placed along same axis as shown. If distance between their centre is 10 cm, find net magnetic field at of point P.

• A. $\frac{50\mu_{0}}{\sqrt{5}}$ T
• B. $\frac{28\mu_{0}}{\sqrt{5}}$ T
• C. $\frac{56\mu_{0}}{\sqrt{5}}$ T
• D. $\frac{56\mu_{0}}{\sqrt{3}}$ T

Answer 1

Answer: (C)

At point P, magnetic field will be in same direction by both coils.
B = B₁ + B₂$\quad$$\quad$ and$\quad$ $\quad$ B₁ = B₂
$B=\frac{\mu_{0}ir^{2}}{2\left(r^{2}+n^{2}\right)^{\frac{3}{2}}}\times2$
$B=\frac{\mu_{0}ir^{2}}{\left(r^{2}+n^{2}\right)^{\frac{3}{2}}}$
$B=\frac{\mu_{0}\times\frac{7}{2}\times\left(0.1\right)^{2}}{\left[\left(0.1\right)^{2}+\left(0.05\right)^{2}\right]^{\frac{3}{2}}}=\frac{56\mu_{0}}{\sqrt{5}}T$