Q. A current carrying coil is subjected to a uniform magnetic field. The coil will orient so that its plane becomes
A) Inclined at $45{^\circ}$ to the magnetic field
B) Inclined at any arbitrary angle to the magnetic field
C) Parallel to the magnetic field
D) Perpendicular to the magnetic field
Explanation
(d) Torque $\overrightarrow{\tau} = \overrightarrow{M} \times \overrightarrow{B}$ or $\ \ \ \ \ \tau = BM\sin\theta,\ \ $where $\overrightarrow{M}$ is perpendicular to the plane of the coil. Due to this torque, the coil will orient itself so that the torque on the coil is zero. $ie,\ \theta = 0^{0}.It\ \ means\ \overrightarrow{M}$ is parallel to $\overrightarrow{B}$. So, the plane of the coil is perpendicular to this direction of magnetic field.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.