Maxwell’s Fields#
Example 1: Wave Properties in Everyday Life#
The Question:
What are the wavelengths of:
the lowest C on a piano (32.7 Hz);
WKAR AM radio radiation (871 kHz on your radio dial)?
Assume that the speed of sound in air is 341 m/s and that the speed of light in a vacuum is \(3\times 10^{8}\) m/s.
The Answer:
We can easily use the relation for wavelength, frequence, and wave speed twice to find these.
\[
\lambda = v/f \text{ so:}
\]
\[
\text{1. }\lambda(\text{low C)} = \frac{341 \text{ m/s }}{32.7 \text{ s}^{-1}} = 10.7\text{ m}
\]
\[
\text{2. }\lambda(\text{WKAR)} = \frac{3\times 10^{8} \text{ m/s }}{871 \times 10^{3} \text{ s}^{-1}} = 344.4\text{ m}
\]