The shadow method is used for measurement of the outer diameter of an optical fiber. The apparatus employs a rotating mirror with an angular velocity of 4 rad/s which is located at 10 cm from the photo detector. Compute the shadow velocity.

The shadow method is used for measurement of the outer diameter of an

1.	The shadow method is used for measurement of the outer diameter of an optical fiber. The apparatus employs a rotating mirror with an angular velocity of 4 rad/s which is located at 10 cm from the photo detector. Compute the shadow velocity.
A.	0.1 m s<sup>-1</sup>
B.	0.4 m s<sup>-1</sup>
C.	0.87 m s<sup>-1</sup>
D.	1 m s<sup>-1</sup>
Answer» C. 0.87 m s<sup>-1</sup>