Question

Light travels with a speed of 3 × 10⁸ m/s in vacuum. Sunlight takes 8.3 minutes to reach the earth. Calculate the distance between the earth and the sun.

Answer 1

$$\begin{gathered} \mathrm{Given}: \\ \mathrm{Speed}\mathrm{of}\mathrm{light}=3\times {10}^8\mathrm{m}/\mathrm{s} \\ \mathrm{Time}\mathrm{taken}\mathrm{by}\mathrm{light}\mathrm{to}\mathrm{reach}\mathrm{the}\mathrm{earth}=8.3\mathrm{minutes} \\ 8.3\mathrm{minutes}=8.3\times 60\mathrm{s} \\ =498\mathrm{s} \\ \mathrm{Speed}=\frac{\mathrm{Distance}}{\mathrm{Time}} \\ \mathrm{Distance}=\mathrm{Speed}\times \mathrm{Time} \\ \mathrm{Distance}=3\times {10}^8\mathrm{m}/\mathrm{s}\times 498\mathrm{s} \\ =1494\times {10}^8\mathrm{m} \\ \mathrm{Thus},\mathrm{the}\mathrm{distance}\mathrm{between}\mathrm{the}\mathrm{sun}\mathrm{and}\mathrm{the}\mathrm{earth}\mathrm{is}(1494\times {10}^8)\mathrm{m}. \end{gathered}$$