Umakant Kondapure, Collin Fernandes, Nipun Bhatia, Vikram Bathula and, Ketki Deshpande Solutions for Chapter: Magnetism, Exercise 4: Evaluation Test

Two short magnets with pole strengths of $100 \mathrm{ab} \mathrm{ampere}-\mathrm{cm}$ and $64 \mathrm{ab} \mathrm{ampere}-\mathrm{cm}$are placed with their axes in the same vertical line, with similar poles facing each other. Each magnet has a length of 1 cm. When separation between the nearer poles is $1\mathrm{cm},$ the weight of upper magnet is supported by the repulsive force between the magnets. If $g=1000 \mathrm{cm} {\mathrm{s}}^{-2}$, then the mass of upper magnet is

When magnetised, length of an iron bar

A bar magnet is placed with its north pole towards geographic north. The neutral point will be

A toroid has a core of inner radius $20 \mathrm{cm}$ and outer radius $22 \mathrm{cm}$ around which $3000$ turns of wire are wound. If the current in the wire is $10 \mathrm{A},$ the field along the axis at distance of $2 \mathrm{m}$ from the centre is given by

Choose the incorrect statement.

Which of the following figure correctly depicts magnetic field lines due to a U-shaped magnet?

A ship is sailing due west according to Mariner's compass. If the declination of the place is $18°$ east, what is the true direction of ship?

The earth's magnetic field at the equator is approximately $0.4 \mathrm{G}.$ Then the earth's dipole moment is