The objective fstronomical telescope have focal lengths of 320 cm and 4.0 cm, respectively.
The telescope is used to view Neptune and the final image is set at infinity. The diameter of Neptune is 4.96 107 m, and its distance from Earth at the time of observation is 4.4 1012 m. What is the angle (in milliradians) subtended by the final telescopic image of Neptune?
A) 1.3 mrad B) 0.90 mrad C) 1.5 mrad D) 1.7 mrad E) 1.1 mrad
Question 2
A simple pendulum and a mass oscillating on an ideal spring both have period T in an elevator at rest. If the elevator now moves downward at a uniform 2 m/s, what is true about the periods of these two systems?
A) Both periods would remain the same.
B) Both periods would increase.
C) Both periods would decrease.
D) The period of the pendulum would increase but the period of the spring would stay the same.
E) The period of the pendulum would decrease but the period of the spring would stay the same.
Spitzer Telescope Picture of a galaxy
Examples of objective evaluation
A Radio Telescope in Green Bank, West Virginia
The 300-meter Radio Telescope at Arecibo, Puerto Rico
Einstein telescope.
Einstein telescope