I wanted to know how it is determined uncertainty

nebbione

Sorry in my physics exercises i never heard about gaussian propagation, (talking about mechanics or electrical physics exercises) only about sig.figures...
Anyway on the web can'0t find anything.

mfb

That should give a good idea, with the assumption that the uncertainties are not correlated. Usually that is a good approximation - there is no reason that the length measurement and the time measurement influence each other in the pendulum, for example.

Reogl

is uncertainty applicable with the speed of light? like 3x10^8m/s≥c

mfb

The speed of light in vacuum is exact (by definition) in SI units (and most other scientific systems I think), it does not have any uncertainty.