Question

How many kilometers are in a light year?

Answer 1

light year is the distance traveled by light in one year.

Explanation:

`color(purple)(300,000xx 365.242 xx24 xx60 xx60`

`~~color(green)(9.4607 xx 10 ^12km`

Answer 2

`9.46*10^12km`

Explanation:

Remember that:One light year is the distance travelled by light in one year `(365.25` `days)`

And,

`color(brown)(1` `color(brown)(light` `color(brown)(year~~9.46*10^15m`

Now we need to convert Metres into Kilometres

`color(purple)(1km=1000m`

So,

`rarr1` `light` `year=(9.46*10^15)/1000km`

`rarr=(9.46*10^15)/10^3km`

Remember that, if a positive exponent in the denominator goes to the numerator it becomes a negative exponent

`rarr=9.46*10^15*10^(-3)km`

`color(green)(rArr=9.46*10^12km`

Remember `*` means multiplication (another way of writing `xx`)