Answer
$2.6 \times 10^6$ waves (this example assumes a height of 6.0 feet)
Work Step by Step
Let's assume for this example that a person is six feet tall. Convert this length to nanometers. $$6.0 ft \times \frac{12in}{1.0ft} \times \frac{0.0254m}{1.0in}\times \frac{1.0 \times 10^{9}nm}{1.0m}=1.8\times 10^9nm$$ Use dimensional analysis to find the waves in this distance. $$1.8 \times 10^9nm \times \frac{1wave}{705nm}=2.6\times 10^6waves$$
