Question

If the speed of light is $3\times {10}^8\raisebox{1ex}{$m$}\!\left/ \!\raisebox{-1ex}{$s$}\right.$, determine the distance it takes in $1$light year. Report your results in $km$ and in $m$.

Answer 1

Step 1. Given data:

Speed of light = $3\times {10}^8\raisebox{1ex}{$m$}\!\left/ \!\raisebox{-1ex}{$s$}\right.$

Time = $1$ Light year = $365\times 24\times 3600=3,15,36,000sec$

Step 2. Formula used:

Distance traveled in one light-year $\left(S\right)$ = Speed $\left(v\right)$ x time $\left(t\right)$

$S=v\times t$

Step 3. Calculating distance

Hence, distance $\left(S\right)$ = $$\begin{gathered} 3\times {10}^8\times 3,15,36,000 \\ =9.5\times {10}^{15}m \\ =9.5\times {10}^{12}km \end{gathered}$$

Hence, distance is $9.5\times {10}^{12}kmor9.5\times {10}^{15}m$