Obtain an expression for the mutual inductance between a long straight wire and a square loop of side a as shown in Fig. 6.21. :

Derive expression for the coefficient of mutual inductance between two long solenoids.

Define mutual inductance. Write its SI unit. Derive an expression for the mutual inductance of two long co-axial solenoids of same length wound one over the other.

Write an expression for the magnetic field produced by an infinitely long straight wire carrying a current I, at a short perpendicular distance a from itself.

Use Biot-Savart's law to obtain the expression for the magnetic field at the centre of a coil in the form of a square of sides 2a carrying a current 'I'.

State Gauss' law in electrostatics. Using this law, derive an expression for the electric field due to an infinitely long straight charged wire at a point distant r from it. Plot a graph showing the variation of electric field with r.