# 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.

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