Question

The amplitude modulated (AM)
radio wave bends appreciably round the corners of a $1m\times 1m$ board but
the frequency modulated (FM) wave only negligibly bends. If the average
wavelengths of AM and FM waves are ${\lambda }_a$ and ${\lambda }_f$

• A. ${\lambda }_a$ > ${\lambda }_f$
• B. ${\lambda }_a$ = ${\lambda }_f$
• C. ${\lambda }_a$ < ${\lambda }_f$
• D. we don't have sufficient information to decide about the relation of ${\lambda }_a$ and ${\lambda }_f$

Answer 1

Answer: (A)

${\lambda }_a$ > ${\lambda }_f$

An electromagnetic wave bends round the corners of an obstacle if the size of the obstacle is comparable to the wavelength of the wave. An AM wave has less frequency than an FM wave. So, an AM wave has a higher wavelength than an FM wave and it bends round the corners of a 1 m × 1m board

therefore${\lambda }_a$>${\lambda }_f$

Hence option A is correct.