A rectangular coil of sides ( ) and ( ) lies in the –plane with its centre at the origin

PHYSICS · Subjective · CBSE · Physics · Moving Charges and Magnetism · Moving Charges and Magnetism

Problem

A rectangular coil

PQRS

of sides

4\,\text{cm}

(

PQ

) and

6\,\text{cm}

(

QR

) lies in the

xy

–plane with its centre at the origin. A uniform magnetic field

\mathbf B = 0.25\,\hat i -0.40\,\hat j +0.30\,\hat k\;\text{T}

exists in space. The coil carries a steady current of

3\,\text{A}

in the sense

P \to Q \to R \to S \to P

. (a) Taking the vectors along the sides

PQ

and

PR

as adjacent edges of the rectangle, obtain the area vector

\mathbf A

of the coil. (b) Determine the torque vector

\boldsymbol\tau

acting on the coil due to the magnetic field. (c) Calculate the magnitude of

\boldsymbol\tau

and specify its direction with reference to the coordinate axes.