Distance between the rotating and the fixed mirror (R) = 16 mDistance between the lens and the rotating mirror (b) = 6 mDistance between the source and the lens (a) = 2 mMirror is rotated at a speed of 356 revolutions per second⇒ω=356rev/s=356×2πrad/sec Shift in the image (s)=0.7 m=0.7×103 mIn Foucault experiment, speed of light is given by c=4R2s(R+b)wa​=(0.7)×10−3(16+6)4×(16)2×356×2π×2​=2.975×108 m/s​ Therefore, the required speed of light is 2.975×108 m/s.