Magnetism and Matter — Physics STD 12 Science — Question

The speed of light is 299,792,458m/s.

1. With respect to the earth.
2. With respect to the sun.
3. With respect to a train moving on the earth.
4. With respect to a spaceship going in outer space.

How should a magnetic dipole be placed in a uniform magnetic field so that its potential energy is maximum?

Why there is internal resistance in any cell?

An experimenter measures the length of a rod. Initially the experimenter and the rod are at rest with respect to the lab. Consider the following statements:

1. If the rod starts moving parallel to its length but the observer stays at rest, the measured length will be reduced.
2. If the rod stays at rest but the observer starts moving parallel to the measured length of the rod, the length will be reduced.

A biconcave lens made of a transparent material of refractive index 1.25 is immersed in water of refractive index 1.33. Will the lens behave as a converging or a diverging lens? Give reason.

Special devices, like the klystron valve or the magnetron valve, are used for production of electromagnetic waves. Name the waves and also write one of their applications.

Two wires of equal length are bent in the form of two loops. One of the loops is square shaped whereas the other loop is circular. These are suspended in a uniform magnetic field and the same current is passed through them. Which loop will experience greater torque? Give reasons.

Do two distinct poles actually exist at two nearby points in a magnetic dipole?

Do two distinct poles actually exist at two nearby points in a magnetic dipole?