The magnetic flux through a coil of resistance '$$R$$' changes by an amount '$$\Delta \phi$$' in time '$$\Delta \mathrm{t}$$'. The total quantity of induced electric charge '$$\mathrm{Q}$$' is

Self inductance of a solenoid cannot be increased by

A graph of magnetic flux $$(\phi)$$ versus current (I) is drawn for four inductors A, B, C, D. Larger value of self inductance is for inductor.

A current 'I' produces a magnetic flux '$$\phi$$' per turn in a coil of '$$n$$' turns. Self inductance of the coil is '$$L$$'. The relation between them is