A coil is wound on a core of rectangular crosssection. If all the linear dimensions of the core are increased by a factor 2 and number of turns per unit length of coil remains same, the self inductance increases by a factor of (Assume, permeability is same)

Step-by-step solution

The self-inductance of the coil is given by L = ₀ n ^2 l ~A When n is kept constant and linear dimensions is increased by a factor of 2, the area of cross-section will become 4 A and length with become 2 l . Self-inductance will become 8 times.