Question

One light year is equal to $9.46\times 10^{12}m$. This statement is :
A. True
B. False

Answer 1

Note: The light-year is the distance travelled by light in one Julian year. i.e. \[365.25\]\[\text{days}\]. It is used to measure length in astronomical calculations. This value can be expressed in terms of miles and kms also. Here, we are expressing it in terms of m.

Complete step-by-step answer:
The light-year is the distance travelled by light in one Julian year. i.e. \[365.25\]\[\text{days}\] It is used to measure length in astronomical units and calculations. For eg. The distance between stars and other galactic scales. This value can be expressed in terms of miles and kms also.
We know that speed of light $c=299,792,458 =3 \times 10^{8}m/s$, also $1\;year=365\times 24\times 3600= 3.154\times 10^{7} s$
Then,$1 \;light-year =3 \times 10^{8}\times3.154\times 10^{7}=9.462\times 10^{15}m$.
It is about $9.46\times 10^{12}km$ or $9.46\times 10^{15}m$.
Hence the answer is B. False

Additional Information:
Other astronomical units are light-second, light-minute, light- hour, light-day, light-week and so on, which are fraction of light years, these are used in astronomy, relativistic physics and so on.
$1$light-second=$\dfrac{1}{31557600}$ light-year
$1$light-minute=\[60\] light-seconds
$1$light-hour=\[60\] light-minute
$1$light-day=$24$ light-hour.
$1$light-week=$7$ light-days
$1$light-year= \[365.25\] light-days.

Note: The light-year is generally misinterpreted as a unit of time, due to the word year. But it denotes distance. Here, the power of the \[10's\] is different. In general be careful with the powers and units, when converting the quantities.