A Ruby Laser Beam $\lambda$ = 6943 Nm)is Sent Outwards from a 2

question 32

Multiple Choice

A ruby laser beam ( $\lambda$ = 694.3 nm) is sent outwards from a 2.7-m diameter telescope to the moon,384,000 km away.What is the radius of the big red spot on the moon?

• A)500 m
• B)250 m
• C)120 m
• D)1.0 km
• E)2.7 km