here we know that the speed of the signal is same as the speed of light
so here we will have
[tex]v = 3 \times 10^8 m/s[/tex]
the altitude of the airplane is given as
[tex]h = 1 \times 10^4 m[/tex]
now we know that time taken by the signal to reach the control tower is given as
[tex]t = \frac{d}{v}[/tex]
now it is given as
[tex]t = \frac{1 \times 10^4 }{3 \times 10^8}[/tex]
[tex]t = 3.33 \times 10^{-5} s[/tex]
so above is the time taken by the signal to reach the control tower
