To keep valuable instruments away from the earth's magnetic field, they are enclosed in iron boxes. Explain.

Name the elements of the earth's magnetic field.

Tell the proper reason for the earth's magnetic field to occur.

By which instrument can the presence of magnetic field be determined ?

Explain the magnetic fields of the Earth.

The lines of force due to earth's magnetic field are ....... .

Name the instrument used to determine the direction of magnetic field .

A magnetic needle free to rotate in a vertical plane parallel to the magnetic meridian has its north up pointing down at 22^@ with the horizontal. The horizontal component of the earth's magnetic field at the place is known to be 0.35 G. Determine the magnitude of the earth's magnetic field at the place.

In the magnetic meridian of a certain place, the horizontal component of the earth's magnetic field is 0.26G and the dip angle is 60^(@) . What is the magnetic field of the earth at this location?