A small coil is introduced between the poles of an electromagnet so that its axis coincides with the magnetic field direction. The number of turns is n and the cross-sectional area of the coil is A .

Question

A small coil is introduced between the poles of an electromagnet so that its axis coincides with the magnetic field direction. The number of turns is $n$ and the cross-sectional area of the coil is $A$ . When the coil turns through $18 0^{\circ}$ about its diameter, the charge flowing through the coil is Q. The total resistance of the circuit is $R$ . What is the magnitude of the magnetic induction?

Options:

Answer:

D

Solution:

Induced charge $Q \Rightarrow B = - \frac{n B A}{R} (cos θ_{2} - cos θ_{1}) = - \frac{n B A}{R} (cos 18 0^{\circ} - cos 0^{\circ}) = \frac{QR}{2 n A}$

TestHub · Accepted Answer

Induced charge Q ⇒ B ​ = − R n B A ​ ( cos θ 2 ​ − cos θ 1 ​ ) = − R n B A ​ ( cos 18 0 ∘ − cos 0 ∘ ) = 2 n A QR ​ ​

Physics - Geometrical Optics Question with Solution | TestHub

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