Unit of magnetic dipole moment is
a) ampere meter
b) ampere/meter⁻¹
c) ampere metre²
d) ampere/metre²
A bar magnet of dipole moment ’m’ cut into two equal pieces transverse to its length. Dipole moment of each part is
a) Remain same
b) m/2
c) 2m
d) none of the above
A current carrying small loop behaves like a small magnet. If A be its area and M its magnetic moment, the current in the loop will be
a) M/A
b) A/M
c) MA
d) A²M
A current loop placed in a magnetic field behaves like a
a) Magnetic substance
b) Magnetic pole
c) Magnetic dipole
d) all true
A steel wire of length l has a magnetic moment M .It is then bent into a semicircular arc. The new magnetic moment is
a) M
b) 2M/π
c) M/l
d) Ml
If the angle of dip at two places are 30° and 45° respectively, then the ratio of horizontal components of the earth’s magnetic field at the two places will be
A dip circle is so set that it moves freely in the magnetic meridian. The angle of dip is 40°. Now the dip circle is rotated so that the plane in which the needle moves makes an angle of 30° with the magnetic meridian. In this position, the needle will dip by the angle
A compass needle whose magnetic moment is 60 A m² pointing geographical north at a certain place, where the horizontal component of the earth’s magnetic field is 40 μWb m², experiences a torque
0.2 × 10⁻³ Nm. The declination at this place is
In a permanent magnet at room temperature,
(a) magnetic moment of each molecule is zero
(b) the individual molecules have non-zero magnetic moment which are all perfectly aligned
(c) domains are partially aligned
(d) domains are all perfectly aligned
Magnetic field lines form continuous closed loops
a) magnet is always a dipole
b) magnet is always a monopole
c) magnetic material is permeable
d) none of the above
The direction of magnetic dipole moment is always from
a) North pole to south pole
b)Away from North pole outside magnet
c) South pole to North Pole
d) all of the above