Calculate the electric and magnetic fields produced by the radiation coming from a `100` W bulb at a distance of `3 m`. Assume that the efficiency of the bulb is `25%` and it is a point source.

Biot - Savart's law relates current with the magnetic field produced by it. Using the law derive an expression for intensity of magnetic field at a point at distance x from the center and on the axis of a circular current loop

What is the magnitude of the equatorial and axial fields due to a bar-magnet of length 5.0, qt a distance of 50 cm from its mid-point? The magnetic moment of the bar-magnet is 0.40 A-m^2 .