Author Question: A ruby laser beam (l = 694.3 nm) is sent outwards from a 2.7-m diameter telescope to the moon, ... (Read 52 times)

D2AR0N · **on:** Jul 28, 2018

A ruby laser beam (l = 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

Question 2

Plane waves of ultrasound, f = 51.0 kHz, impinge on a flat plane with a 1.00 cm-wide slit. What is the total angular width (2q) of diffracted sound waves when the speed of sound in air is 340 m/sec.
a. 167
b. 83.6
c. 19.5
d. 41.8
e. 0.11