Solution:
Given,
Distance between mirrors (d) = 45 km = 45000 m,
Speed of prism (n) = 416.7 rev/s,
Faces of prism (m) = 8,
Speed of the light (c) = ?
We have from the Michelson's method
c = 2mnd
= 2 x 8 x 416.7 x 45000
= 300024000 m/s
= 3 x 10^8 m/s
Hence the velocity (speed) of light is determined to be 3 x 10^8 m/s.