Light year, light second calculation explained!

let's quickly understand how to measure

a light here a light here is a measure

of distance and not of time a lot of

people think there is this word ear in

light year so it is supposed to be a

measure of time but no it is a

measurement of distance so to calculate

one light year we have to use a formula

the formula for distance so there is a

very common physics formula which is

distance is equal to speed into time now

for that we have to know the speed of

light so light travels at the speed of

300,000 kilometer per second and in a

more accurate form it is two hundred

ninety nine thousand seven hundred

ninety-two kilometers per second so the

important thing to notice over here is

we are talking about kilometer per

second not kilometer per R so to find

the number of seconds in a year you will

have to do a series of multiplication by

conversions unit so to convert ears to

seconds you will multiply the number of

days in a year times the number of hours

in a day times the number of minutes in

an hour times the number of seconds in a

minute so that's going to be one year

into 365 days per year into 24 hours per

day into 60 minutes per R into 60

seconds per minute and that's going to

give us three crore 15 lakh 36 thousand

seconds and we can write this large

number using scientific notation as

three point one five four into ten to

the power of seven now use all these

variables into the equation and solve so

the equation is distance is equal to

speed into time so the speed of light is

300,000 kilometer per second multiplied

by three point 1 5 4 into 10 to the

power of 7 seconds which has also known

as the number of seconds in a year so

let's quickly do the calculation so the

answer is 9 point 4 6 into 10 to the

power of 12 or nine point five trillion

kilometers so this is how we calculate a