# What is the value of a light year in SI Units?

$\begin{array}{1 1}(A)\;9.467 \times 10^{15} \\(B)\;2.3 \times 10^{7} \\(C)\;9 \times 10^{8} \\(D)\;25 \times 10^{3} \end{array}$

A light year is the distance travelled by light, in vacuum, in one year .
Since velocity of light $= 3 \times 10^8 ms^{-1}$
1 year $=365 \large\frac{1}{4}$$\times 24 \times 60 s$
therefore 1 light year $= (3 \times 10^8 ms^{-1} )$
$\qquad= 9.467 \times 10^{15} m$
Hence A is the correct answer.