Question

The metre is defined as the distance travelled by light in 1/299792458 second.why don't people choose some easier number such as 1/300000000 second?

Answer 1

Speed of light is in vacuum 299,792,458 m/s. Hence, metre is defined on the basis of this speed. Taking some standard easier number would have yielded a small error in the standard value of metre. One second is a big time interval when one wants to set a measure for some standard quantity to a very large accuracy.. Hence, taking one second is not feasible either. Speed of light is exactly 299,792,458 metres per second i.e distance travel by light in 1 sec.. So to defined 1 meter v consider distance travel by light in 1/299792458 sec and if v consider 1/300000000 sec thn we will get approximately 1 meter... and to define 1 meter we cannot consider distance travel by light in 1 sec because that distance will be 299,792,458 metres but,, 1/300,000,000 is a very nice approximation of 1/299,729,458 but afterall they are not same though the diffrence is not much bust on large scales you may encounter some problems such as 100 light years will be significantly greater if we take speed of light 300,000,000m/s instead of 299,729,458m/s.