## College Physics (4th Edition)

(a) The wavelength of the EM waves is $5.0\times 10^6~m$ (b) This wavelength is 78% of the length of the Earth's radius. (c) These waves are radio waves.
(a) We can find the wavelength of the EM waves: $\lambda = \frac{c}{f}$ $\lambda = \frac{3.0\times 10^8~m/s}{60.0~Hz}$ $\lambda = 5.0\times 10^6~m$ The wavelength of the EM waves is $5.0\times 10^6~m$ (b) We can find the ratio of this wavelength to the Earth's radius: $\frac{5.0\times 10^6~m}{6.38\times 10^6~m} = 0.78$ This wavelength is 78% of the length of the Earth's radius. (c) These waves are radio waves, which are the longest waves in the EM spectrum.