Question

An observer uses a 10 sided mirror to measure the speed of light. A clear image occurs every one-tenth of a rotation when the mirror is rotating at 4.31x10^2 rev/s. The total path of the light pulse is 60 km, measured from the light source to the mirrors and reflected back to the observer. What is the speed of light calculated from this data?

a. 3.87x10^-9 m/s
b. 2.59x10^5 m/s
c. 1.39x10^2 m/s
d. 2.59x10^8 m/s

Answer 1

N= 0.1 rev
n= 4.31•10² rev/s
t=N/n = 0.1/4.31•10² = 2.32 •10⁻⁴ s
v=s/t =60000/2.32•10⁻⁴=2.59•10⁸ m/s
Ans. d