Question
The speed of light is approximately 3 × 10⁸ metres per second. The distance from Earth to a star is 4.2 × 10¹⁶ metres.
(a) Calculate the time, in seconds, for light to travel from the star to Earth. Give your answer in standard form. (3 marks) (b) Convert this time to years. Use 1 year ≈ 3.15 × 10⁷ seconds. Give your answer to 2 significant figures. (3 marks)
6 marks · take your time before peeking.
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