#### Answer

(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.

#### Work Step by Step

(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.