Question

What is our best evidence that earth has a magnetic field?
A. All things fall towards earth’s centre.
B. A compass needle lines up with it.
C. Winds blow from east to west.
D. Earth’s oceans all have currents.

Answer 1

Hint:Let us know about the earth’s magnetic field. The magnetic field that extends from the Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emerging from the Sun, is known as the geomagnetic field.

Complete answer:
Electric currents generated by the movements of convection currents of molten iron and nickel in the Earth's outer core generate the magnetic field; these convection currents are triggered by heat escaping from the core, a natural phenomenon known as a geodynamo.

Let us know about compasses. A compass is a tool for navigation and geographic orientation that displays the cardinal directions. It usually consists of a magnetised needle or other element that can pivot to align itself with magnetic north, such as a compass card or compass rose. Other devices, such as gyroscopes, magnetometers, and GPS receivers, could be employed. The best proof is to use a direction compass to see where the north position points, and you will notice that it always points to the north and south poles.

Hence, the correct answer is option B.

Note:The Earth's magnetic field at its surface has a magnitude ranging from\[25{\text{ }}to{\text{ }}65{\text{ }}T\]. It is approximated by the field of a magnetic dipole currently tilted at an angle of around \[11\] degrees with regard to the Earth's rotational axis, as if a giant bar magnet were positioned at that angle through the Earth's core.