JEE Main · 2023 · 08 Apr 2023 · Shift 2 · Semiconductors

The power radiated by a short linear antenna of length $l$ depends on how long the antenna is compared with the wavelength it carries. Antenna theory gives the radiated power as proportional to the square of this ratio, $P\propto {\left(\frac{l}{\lambda }\right)}^2$, which is why an antenna only a small fraction of a wavelength long radiates very feebly. The power radiated is proportional to ${\left(\frac{l}{\lambda }\right)}^2$.