Maxwell’s Fields

Maxwell’s Fields#

Example 1: Wave Properties in Everyday Life#

The Question:

What are the wavelengths of:

  1. the lowest C on a piano (32.7 Hz);

  2. 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.

\[ \lambda = v/f \text{ so:} \]
\[ \text{1. }\lambda(\text{low C)} = \frac{341 \text{ m/s }}{32.7 \text{ s}^{-1}} = 10.7\text{ m} \]
\[ \text{2. }\lambda(\text{WKAR)} = \frac{3\times 10^{8} \text{ m/s }}{871 \times 10^{3} \text{ s}^{-1}} = 344.4\text{ m} \]