Answer:
a) [tex]t = 7.333\times 10^{-4}\,s[/tex], b) [tex]t = 501.267\,s[/tex], c) [tex]t = 5000\,s[/tex], d) 7200 years ago.
Explanation:
The speed of light is equal to [tex]3 \times 10^{8}\,\frac{m}{s}[/tex].
a) Radio signal is a form of electromagnetic waves, which does not need a medium in which to propagate. The time required is:
[tex]t = \frac{220000\,m}{3\times 10^{8\,\frac{m}{s} }}[/tex]
[tex]t = 7.333\times 10^{-4}\,s[/tex]
b) The time required is:
[tex]t = \frac{3.8\times 10^{8}\,m+1.5\times 10^{11}\,m}{3\times 10^{8}\,\frac{m}{s} }[/tex]
[tex]t = 501.267\,s[/tex]
c) The round-trip travel time is:
[tex]t = \frac{2 \cdot (7.5\times 10^{11}\,m)}{3\times 10^{8}\,m}[/tex]
[tex]t = 5000\,s[/tex]
d) A light-year is distance unit which is equal to the distance travelled by light during one year. Hence, the observation of the supernova happened about 7200 years ago.
