A hollow, right circular cone of base radius R and height h, with its tip at the origin is rotating about the Z-axis with an angular velocity , as shown in the figure. The cone carries a total charge Q uniformly distributed on its curved surface. The magnitude of magnetic field at a point (0, 0, z), where z R and z h, is n 04 QR2 z3. The value of n is: [figure]
Moving Charges and Magnetism
Previous year questions with solutions · 2024 – 2026
Year-wise statistics questions · papers · average per paper · weightage
| Year | Questions | Papers | Avg / paper | Weightage |
|---|---|---|---|---|
| 2026 | 2 | 2 | 1 | 5.88% ↑88.2% |
| 2025 | 1 | 2 | 0.5 | 3.12% ↓64.6% |
| 2024 | 3 | 2 | 1.5 | 8.82% |
A conducting solid sphere of radius R and mass M carries a charge Q. The sphere is rotating about an axis passing through its center with a uniform angular speed . The ratio of the magnitudes of the magnetic dipole moment to the angular momentum about the same axis is given as Q2M. The value of is
A thin stiff insulated metal wire is bent into a circular loop with its two ends extending tangentially from the same point of the loop. The wire loop has mass m and radius r and it is in a uniform vertical magnetic field B0, as shown in the figure. Initially, it hangs vertically downwards, because of acceleration due to gravity g, on two conducting supports at P and Q. When a current I is passed through the loop, the loop turns about the line PQ by an angle given by [figure]
- = rIB0/(mg)
- = 2 rIB0/(mg)
- = rIB0/(2mg)
- = mg/( rIB0)