Assertion (A): | Gauss's law for magnetism states that the net magnetic flux through any closed surface is zero. |
Reason (R): | The magnetic monopoles do not exist. North and South poles occur in pairs, allowing vanishing net magnetic flux through the surface. |
1. | (A) is True but (R) is False. |
2. | (A) is False but (R) is True. |
3. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
4. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
Statement I: | The magnetic field of a circular loop at very far away point on the axial line varies with distance as like that of a magnetic dipole. |
Statement II: | The magnetic field due to magnetic dipole varies inversely with the square of the distance from the centre on the axial line. |
1. | Statement I is correct and Statement II is incorrect. |
2. | Statement I is incorrect and Statement II is correct. |
3. | Both Statement I and Statement II are correct. |
4. | Both Statement I and Statement II are incorrect. |
A bar magnet is hung by a thin cotton thread in a uniform horizontal magnetic field and is in the equilibrium state. The energy required to rotate it by \(60^{\circ}\) is \(W\). Now the torque required to keep the magnet in this new position is:
1. \(\dfrac{W}{\sqrt{3}}\)
2. \(\sqrt{3}W\)
3. \(\dfrac{\sqrt{3}W}{2}\)
4. \(\dfrac{2W}{\sqrt{3}}\)
A magnetic needle suspended parallel to a magnetic field requires \(\sqrt{3}~\text{J}\) of work to turn it through \(60^\circ\)
1. \(3\) N-m
2. \(\sqrt{3} \) N-m
3. \(\frac32\) N-m
4. \(2\sqrt{3}\) N-m
A short bar magnet of magnet moment \(0.4\) is placed in a uniform magnetic field of \(0.16\) . The magnet is in stable equilibrium when the potential energy is:
1. \(0.064\) J
2. \(-0.064\) J
3. zero
4.\(-0.082\) J
1. | motion remains SHM with time period = \(\frac{T}{2}\) |
2. | motion remains SHM with time period = \(2T\) |
3. | motion remains SHM with time period = \(4T\) |
4. | motion remains SHM with time and period remains nearly constant |