Question 351 of 380

A galvanometer coil has 500 turns and each turn has an average area of $3\times {10}^{-4}{m}^{2}$. If a torque of $1.5Nm$ is required to keep this coil parallel to a magnetic field when a current of $0.5A$ is flowing through it, the strength of the field (in $T$) is _________ .

Your answerCheck answer

Show answer and solution▾

Answer: 20

$\tau =\left|\vec{M}\times \vec{B}\right|=NiAB\sin \left(90^{\circ}\right)$
$=NiAB=NiSB$
$\Rightarrow B=\dfrac{\tau }{NiS}=\dfrac{1.5}{500\times 0.5\times 3\times {10}^{-4}}=20$