A current loop in a magnetic field - Vidyadip

MCQ

A current loop in a magnetic field

A
experiences a torque whether the field is uniform or non uniform in all orientations.
B
can be in equilibrium in one orientation.
C
can be in equilibrium in two orientations,both the equilibrium states are unstable.
D
can be in equilibrium in two orientations, one stable while the other is unstable.

✓

Answer

When a current loop is placed in a magnetic field it experiences a torque. It is given by

$\vec{\tau}=\vec{M} \times \vec{B}$

where, $\vec{M}$ is the magnetic moment of the loop and $\vec{B}$ is the magnetic field.

or $\quad \tau=M B \sin \theta$ where $\theta$ is angle between $M$ and $B$ When $\vec{M}$ and $\vec{B}$ are parallel (i.e. $\theta=0^{\circ}$ ) the equilibrium is stable and when they are antiparallel (i.e. $\theta=\pi$ ) the equilibrium is unstable.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "MCQ" from Magnetic Effect of Current→Magnetic Effect of Current — all question types→JEE physics STD 12 Science question papers→CBSE Board STD 12 Science question papers→CBSE Board question paper generator→

Similar questions

A rubber pipe of density $1.5 \times 10^3 N / m ^2$ and Young's modulus $5 \times 10^6 N / m ^2$ is suspended from the roof. The length of the pipe is $8 m$. What will be the change in length due to its own weight

Two light sources are said to be coherent if they are obtained from

One mole of an ideal monoatomic gas is heated at a constant pressure of one atmosphere from $0^{\circ} \mathrm{C}$ to $100^{\circ} \mathrm{C}$. Then the change in the internal energy is

A body is thrown vertically upwards. If air resistance is to be taken into account, then the time during which the body rises is

In the given figure, which of the diodes are forward biased ?

$P-V$ diagram of a diatomic gas is a straight line passing through origin. The molar heat capacity of the gas in the process will be

In hydrogen spectrum the wavelength of $H _\alpha$ line is $656 nm$ whereas in the spectrum of a distant galaxy, $H _\alpha$ line wavelength is $706 nm$. Estimated speed of the galaxy with respect to earth is [IIT-JEE 1999; UPSEAT 2003]

If an ideal gas is compressed isothermally then

A mass $m$ performs oscillations of period $T$ when hanged by spring of force constant $K$. If spring is cut in two parts and arranged in parallel and same mass is oscillated by them, then the new time period will be

When load of $5 kg$ is hung on a wire then extension of $3 m$ takes place, then work done will be