A magnetic needle is disposed inside a horizontal coil. In the abscence of any electric current the needle is observed to get oriented in a direction perpendicular to the x'x of the coil.
a) what is the direction of the terrestrial magnetic field.
b) A current I is allowed in the coil the magnetic needle deviates through an angle alpha.
Determine the direction of the current in the coil.
Calculate the intensity of the magnetic field created by the coil