define si unit of 1 metre for length which physical quantity is measure by Copernicus method
Answers
We have to define SI unit of 1 metre for length. And also we have to discuss about Copernicus method.
Solution : according to international system of units, 1 metre, unit of length, is the distance travelled by light in vacuum medium in 1/299,792,458 second.
As we know, speed of light in vacuum is 299,792,458 m/s
So, distance = speed of light × time
= 299,792,458 m/s × 1/299,792,458 s
= 1m
Copernicus method : there are lots of method to find the distance between objects like, parallax method, Kepler's 3rd law etc.
Copernicus method is used to find the distance between those planets which are near to the sun rather than that of earth. According to this method,
1 A.U (astronomical unit) = 1.496 × 10¹¹ m
Therefore Length is measured by Copernicus method.