The Earth’s Magnetism

A telephone cable at a place has four long straight horizontal wires carrying a current of 1.0 A in the same direction east to west. The earth’s magnetic field at the place is 0.39 G, and the angle of dip is 35°. The magnetic declination is nearly zero. What are the resultant magnetic fields at points 4.0 cm below the cable?

What is the angle of dip at a place where the horizontal component `(B_H)` and vertical component `(B_V)` of earth’s magnetic field are equal : 

Solve the following problem.

A magnet makes an angle of 45° with the horizontal in a plane making an angle of 30° with the magnetic meridian. Find the true value of the dip angle at the place.

Choose the correct option.

A place where the vertical components of Earth's magnetic field is zero has the angle of dip equal to

Which of the following independent quantities is not used to specify the earth’s magnetic field?

A conducting rod held horizontally along East- West direction is dropped from rest from a certain height near the Earth’s surface. Why should there be an induced emf across the end of the rod? Draw a plot showing the instantaneous variation of emf as a function of time from the instant it begins to fall.

The net magnetic flux through any closed surface, kept in a magnetic field is ______.

The earth’s core is known to contain iron. Yet geologists do not regard this as a source of the earth’s magnetism. Why?