Question

At two corners A and B of an equilateral triangle ABC, a south and north pole each of strength $30A-m$ are placed. If the side of the triangle is 1m. The magnetic induction at C is :

• A. $3\times {10}^{-6}T$
• B. $4\times {10}^{-6}T$
• C. $8\times {10}^{-6}T$
• D. $2\times {10}^{-6}T$

Answer 1

The correct option is A $3\times {10}^{-6}T$

$P=30Am$

$B_1=\frac{{\mu }_{0}P}{4\pi d^2}$

$=\frac{{10}^{-7}\times 30}{12}$

$=3\times {10}^{-6}$

$B_2=\frac{{\mu }_{0}P}{4\pi d^2}$

$=3\times {10}^{-6}$

$B=\sqrt{B_1^2+B_2^2+2B_1{B}_2\cos {120}^o}$

$=B_1$

$=3\times {10}^{-6}T$