(a) The distance to a star is approximately 8.64 ✕ 1018 m. If this star were to burn out today, in how many years would we see i
t disappear? years (b) How long does it take sunlight to reach Earth? minutes (c) How long does it take for a microwave radar signal to travel from Earth to the Moon and back? (The distance from Earth to the Moon is 3.84 ✕ 105 km.) s
2 answers:
Answer:
(a) 913.874 Years.
(b) 8 minutes.
(c) 2.56177 Seconds.
Explanation:
(a) Following Equation relates Distance to Velocity and time.
(S is for Distance,
in it we have.
S = , V = 299792458m/s (Velocity of Light).
t = ?
Rearranging and solving for time gives us. t =
which when converted to years , we have t = 913.874years, that is how long it will take for us to notice that the star has been burned out.
(b) it take 8 minutes for sun light to reach earth, how.? because distance from earth to sun is 150.46 million Km. doing same calculations as in (a) gives us 8 minutes.
(c) Distance to moon and back is twice as much, because obviously it is round trip, so S = 2 x 3.84x10^5Km.
using same logic as in (a) and (b) we get t = 2.56177 seconds. that is how long light takes to reach moon and come back.
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