Question 3 :
<span class="wysiwyg-font-size-medium"><span class="wysiwyg-font-size-medium"><p>A line joining places of same declination is called</p>

Question 4 :
The magnetic induction field strength at a distance 0.2 m on the axial line of a short barmagnet of moment 3.6 Am$^{2}$is

Question 6 :
If the earth does not rotate on its axis, the change in the weight of a body at the equator would be about (Take radius of earth-6400 km)

Question 7 :
<span class="wysiwyg-font-size-medium"><span class="wysiwyg-font-size-medium"><p class="wysiwyg-text-align-left">In the hystersis cycle, the value of H needed to make the intensity of magnetisation zero is called</p>

Question 8 :
Assertion (A): Poles of a magnet can never be separated.<br>Reason (R) : Since, each atom of a magnetic material is a magnet in itself.

Question 12 :
Magnetic susceptibility of diamagnetic materials is of the order of (SI units) :

Question 13 :
A magnetizing field of $2 \times 10^3 A m^{-1}$ produces a magnetic flux density of $8 \pi T$ in an iron rod. The relative permeability of the rod will be:

Question 14 :
A student uses a magnetic compass to perform a laboratory experiment in the Northern Hemisphere. She then carries the same magnetic compass with her to the Southern Hemisphere, taking care not to damage the compass in any way. When she reaches her destination at the equivalent latitude and longitude in the Southern Hemisphere, she prepares to perform the same laboratory experiment. The student looks at the compass before performing the experiment to see if the compass needle has changed. How has the compass changed?

Question 15 :
The earth behaves as a magnet with magnetic field pointing approximately from the geographic

Question 16 :
The magnetic moment of a magnet of mass $75$ $g$ is $9 \times 10^{-7} Am^2$. If the density of the material of magnet is $7.5 \times 10^{3}$ then intensity of magnetisation will be

Question 20 :
A magnetised steel wire $31.4 cm$ long has a pole strength of $0.2 A m$. It is then bent in the form of a semicircle. Calculate the magnetic moment of this needle.

Question 22 :
The resultant magnetic field at the center of a bar magnet is zero.<br>

Question 23 :
Assertion : Lenz's Law violates the principle ofconservation of energy<br>Reason : Induced emf always opposes thechange in magnetic flux responsible for itsproduction.<br>

Question 24 :
The tangent drawn at any point on the magnetic lines of force gives direction of mangetic field at that point.<br/>

Question 25 :
There are two current carrying planar coils each made from identical wires of length L. $C_1$ is circular (radius R) and $C_2$ is square(side a). They are so constructed that they have same frequency of oscillation when they are place in the same uniform magnetic field $\vec{B}$ and carry the same current. Find a in terms of R.