Exam 3: Light and Telescopes

The secondary mirror of a telescope whose primary mirror is 4 m in diameter has a diameter of 0.5 m. What fraction of the incoming light is obstructed by this secondary mirror?

A Cassegrain reflecting telescope is constructed using a

The radio station has a broadcast frequency of 89.7 megahertz. What is the energy of a single photon in this radio beam (in joules)?

In general, doubling the diameter of an optical telescope will

Research observatories do NOT use Newtonian reflectors because they

Who first proved that light is a wave?

What factor has seriously reduced the effectiveness over the last few years of the 5-m Hale telescope on Mount Palomar, California, formerly the largest telescope in the world?

The wavelength of green light is about 500 nanometers. What is this length in meters?

In 1801, Thomas Young performed a crucial experiment on the nature of light when he

A radio telescope

All forms of light have what property in common?

An electrical spark, such as lightning, generates electromagnetic radiation over a wide range of wavelengths. How much longer will a pulse of radio energy take to travel between two detector stations 100 m apart than will a pulse of ultraviolet radiation from the same spark?

When the Galileo spacecraft reached Jupiter on December 7, 1995, Jupiter was almost at conjunction with the Sun. Given that it takes 8 1/3 minutes for light to travel a distance of 1 au, how long did it take Galileo's signals to reach Earth from Jupiter? (A diagram might help to envision this configuration.)

The prime focus of a reflecting telescope is reached by light after

What is the source of MOST of the gravitational waves detected directly over the past several years?

The BEST Earth-based sites for modern large astronomical telescopes, which provide the least seeing effects on astronomical images, are

Which one of these properties does the neutrino NOT possess?

Why did Karl Jansky believe the source of radio static he was detecting in 1932 was not from terrestrial sources?

Compared to the speed of visible light in a vacuum (or in space), the speed of visible light in water or in glass is

Which of these types of telescopes is MOST seriously affected by chromatic aberration?