Why is it inportant for scientists all over the world to use the same system of measurement

Explanation:

It allows scientists to be able to collaborate and also peer review other scientists' works. If scientists did not use the same SI units, it would be difficult to replicate experiments in other parts of the world by other scientists.  It would therefore also be hard to improve on experiments and increase scientific knowledge. Standard SI unit across the world improves communication between global scientists.

the duration of a photographic flash is related to an rc time constant, which is 0.100 μs for a certain camera.