A coil has 300 turns, each of area 0.05 m2. (i) Find the current throu

1.	A coil has 300 turns, each of area 0.05 m2. (i) Find the current through the coil for which the magnetic moment of the coil will be 4.5 A-m2. (ii) It is placed in a uniform magnetic field of induction 0.2 T with its magnetic moment making an angle of 30° with \(\vec B\). Calculate the magnitude of the torque experienced by the coil.
Answer» Data : N = 300, A = 0.05 m², M = 4.5 A ∙ m², B = 0.2 T, θ = 30° (i) M = NIA ∴ The current in the coil, I = \(\cfrac{M}{NA}\) = \(\cfrac{4.5}{300\times0.05}\) = 0.3 A (ii) The magnitude of the torque, τ = MB sin θ = 4.5 × 0.2 × sin 30° = 0.9 × \(\cfrac12\) = 0.45 N∙m

A coil has 300 turns, each of area 0.05 m2. (i) Find the current through the coil for which the magnetic moment of the coil will be 4.5 A-m2. (ii) It is placed in a uniform magnetic field of induction 0.2 T with its magnetic moment making an angle of 30° with \(\vec B\). Calculate the magnitude of the torque experienced by the coil.

Answer»

Data : N = 300, A = 0.05 m²,

M = 4.5 A ∙ m², B

= 0.2 T, θ = 30°

(i) M = NIA

∴ The current in the coil,

I = \(\cfrac{M}{NA}\) = \(\cfrac{4.5}{300\times0.05}\) = 0.3 A

(ii) The magnitude of the torque,

τ = MB sin θ = 4.5 × 0.2 × sin 30°

= 0.9 × \(\cfrac12\) = 0.45 N∙m