The speed of light in vacuum is,
[tex]c= 3\times 10^8 \ m/s[/tex].
To calculate the time, we use the relation,
[tex]d= c\times t \\\\\ or \ t=\frac{d}{c}[/tex]
Here, d is distance and its value is given 3. 60 km, and c is speed of light.
Therefore,
[tex]t = \frac{3.60\times 10 ^3 m}{3\times 10 ^8 m/s} =1.2 \times 10^{-5} \ s[/tex]
In nanoseconds,
[tex]1 ns = 10^{-9} s[/tex]
[tex]1 \ s = \frac{1 \ n s}{10^{-9 } }[/tex]
Therefore,
[tex]t = 1.2 \times 10^{ -5} \times \frac{1 \ ns}{10^{-9} } = 1.2 \times 10^4 \ ns[/tex]
