# Calculate the electric field produced by the radiation coming from a $100\: W$ bulb at a distance of $3\: m$. Assume that the efficiency of the bulb is $2.5\ %$ and it is a point source.
$\begin {array} {1 1} (a)\;29 V/m & \quad (b)\;4.07 V/m \\ (c)\;2.9 V/m & \quad (d)\;40.7 V/m \end {array}$