Question

An electromagnetic wave radiates outwards from a dipole antenna, with $E_0$ as the amplitude of its electric field vector. The electric field $E_0$ which transports significant energy from the source falls off as

• A. $\frac{1}{r^3}$
• B. $\frac{1}{r^2}$
• C. $\frac{1}{r}$
• D. remains constant.

Answer 1

The correct option is C $\frac{1}{r}$

A diode antenna radiates the electromagnetic wave outwards. The amplitude of electric field vector $\left(E_0\right)$ which transports significant energy from the source falls intensity inversely as the distance (r) from the antenna,

i.e,$E_0\propto \frac{1}{r}$