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