Q: Define retentivity and coercivity. Draw the hysteresis curve for soft iron and steel. What do you infer from these curves?
Q: a) The force between two magnetic poles separated by a distance 'd' in air is 'F'. At what distance between them does the force becomes doubled?
b) If B is the magnetic field produced at the centre of a circular coil of one turn of length 'l' carrying current 'i', then what is the magnetic field at centre of the same coil which is made into 10 turns?
Q: A bar magnet, held horizontally, is set into angular oscillation in the Earth's magnetic fields. It has time periods T1 and T2 at different places, where the angles of dip are θ1 and θ2 respectively. Deduce an expression for the ratio of the resultant magnetic fields at the two places.
Q: Explain the elements of the Earth's magnetic field and draw a sketch showing the relation between the vertical component, horizontal component and angle of dip.
Q: A small magnetic needle is set into oscillations in a uniform magnetic field. Obtain an expression for the period of oscillation.