A long, straight wire of radius 5.0 mm carries a current of 20A. i) Calculate the magnetic field at the surface of the wire, and ii) calculate the perpendicular distance, from the axis of the wire, at which the magnitude of magnetic field will be half of

its value at the wire surface.

The magnitude of work done in taking a unit positive charge in electric field E from point A to point B is given by:

Show that the value of the line integral of the electric field (right hand side of the above equation) does not depend on the path taken to move the unit positive charge

from point A to B.

The line density of charge in a wire is 0.2 Cm⁻¹. If this wire is symmetrically enclosed, along its length, by a cylindrical surface of radius 1 m and length 1.5 m, calculate i) the electric flux through the cylindrical surface, and ii) the electric field

at the curved surface of the cylinder.

An electron and a proton, moving with equal velocity, enter a region of uniform, perpendicular magnetic field. Calculate the ratio of the radii of their circular paths in

the field.

State and explain the boundary condition for the displacement vector D at the

boundary separating two dielectric media.

What is the difference between ohmic conductor and non-ohmic conductor? Give

one example each and draw their IV characteristic curves.

A parallel plate capacitor is made of two rectangular aluminium sheets of lateral dimensions 500 mm and 20 mm. The space between the plates is filled with

polystyrene and the separation between plates is 0.15 mm. Calculate the capacitance of the capacitor and the value of the maximum potential difference that can be applied across the capacitor without dielectric breakdown. Take the dielectric constant of polystyrene as 2.6 and the value of the maximum electric field that

polystyrene can withstand as 25×10⁶ Vm⁻¹.