Question

. An electromagnetic radio wave is received by a transmitter before it is converted to a sound wave. The radio wave has a wavelength of 23,076 m and a frequency of 13,000 Hz. What velocity is the wave traveling at before the transmitter converts it to a sound wave? A 1.76 m/s B 0.56 m/s C 3.31 × 102 m/s D 3.00 × 108 m/s

Answer 1

By definition, the wavelength of an electromagnetic wave is calculated using the following formula:

$\lambda = \frac{c}{f}$

Where:

\lambda = wavelength

c = speed of light = $3\ x\ 10^8\ m/s$

f = frequency of the wave.

This relation means that the division of the wavelength λ between the frequency f is always equal to the speed of light.

Thus:

the velocity v of this wave must be equal to c.

$v = f\lambda$

$v = (23\ 076\ m) (13\ 000\ Hz)$

$v = 2.9999\ x\ 10^8 = c$

Finally the correct answer is D. $3.00\ x\ 10^8$