Question

Convert 1 light year into km

• A. $9.46\times {10}^{12}m$
• B. $9.46\times {10}^{12}km$
• C. $9.46\times {10}^{15}m$
• D. $9.46\times {10}^{15}km$

Answer 1

The correct option is B

$9.46\times {10}^{12}km$

A light year is the distance travellled by light in vacuum, in one year i.e.,

1 light year = speed of light $\times$ 1 year = $3\times {10}^{8}m{s}^{-1}\times (365\times 24\times 60\times 60s)=9.46\times {10}^{15}m=9.46\times {10}^{12}km$