Question

An electromagnetic wave radiates outwards from a dipole antenna, with $E_0$ as the amplitude of its electric field vector. The electric field $B_0$ 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

Answer: (C)

$\frac{1}{r}$

An antenna that produces the Electromagnetic wave are radiated outwards. The amplitude of electric field vector $\left(E_0\right)$. This electric field vector transports the energy from the source through the medium.

The electric field intensity of the wave from the source at a distance is inversely proportional to the distance between the source and the point.

$E_0=\frac{1}{r}$

Option $\left(C\right)$ is correct.