the meters is defined as the distance by light in 1/299,792,458 second. why didn't people choose some easier number such as 1/300,000,000 second?why not 1 second?
Answers
This is a convenient way to measure 1 meter. The speed of light is always constant in vacuum and therefore can be relied upon. With the help of the definition of the second, scientists were able to calculate 1 meter in terms of the distance traveled by light. Actually, an earlier definition was based on the length of a prototype rod whose length was taken to be 1 meter and became standard. That very same length is now measured according to this definition (this definition was adopted in 1983).
The distance traveled by light in 1 second is very large and cannot be used in calculations for practical purposes. If 1 meter was considered to be the distance traveled by light in 1 second, then that would be a huge quantity (you'd have to go nearly 75 times around the earth's equator to cover that distance!).
Google up 'History of the Meter' for a Wikipedia page giving a full explanation.