Question

Magnetic dipole moment is a:

(A) scalar quantity
(B) vector quantity
(C) constant
(D) none of these

Answer 1

Hint:
In order to find out magnetic dipole moment is a vector quantity or a scalar quantity, first we need to know what is magnetic dipole moment, how it is calculated and what is it exact formula and what are the quantity related to which affects its value and finally we will be able to tell is it a scalar or vector quantity.





Complete step by step solution:
First start with what is magnetic dipole moment:
The magnetic dipole moment is the magnetic field strength and the direction or orientation of a magnet or other objects such as electric current loops or molecules that produce a magnetic field. It is equal to the electric current flowing through the loop multiplied by the area of the electric current loop and its direction is determined by the right hand rule for rotations.

Now, we know that the magnetic dipole moment is given by:
$\vec M = Ni\vec A$
Where, $\vec M$ is magnetic dipole moment.
N is the number of turns in the coil or loop.
$i$ is the electric current flowing through the loop.
\[\vec A\] is the area vector of the current loop.\[\]

From the above formula it is clear that the magnetic dipole moment \[\vec M\] is a vector quantity and its direction is the same as the area vector \[\vec A\] direction.

Hence the correct answer is Option(B).





Note:
Here it was very easy to find whether the magnetic dipole moment is a scalar or vector quantity from the formula as it has an area vector in it hence it can never be a scalar quantity. Also magnetic dipole moment cannot be constant as it has variable quantity in its formula such as current, no of turns and area vector.