# Question #33e1f

Mar 1, 2016

We need to use:
Speed of light = frequency x wavelength

hence
Frequency = speed of light / wavelength

And
Wavelength = speed of light / frequency

#### Explanation:

The speed of light is $c = 3 \times {10}^{8} m {s}^{-} 1$

So question (a) is $\frac{c}{290 \times {10}^{-} 9} = 1.03 {\times}^{15} H z$

This in the ultraviolet part of the spectrum

And for (b) $\frac{c}{7.6 \times {10}^{10}} = 3.9 \times {10}^{-} 3 m$
This is in the microwave part of the spectrum

For (c) we can work out distance by multiplying speed by time taken $\left(3 \times {10}^{8}\right) \times \left(25.5 \times {10}^{-} 10\right) = 0.765 m$