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.
Uranus's aurorae against its equatorial rings, imaged by the Hubble telescope. Unlike the auror
The same star field photographed with (a) a ground-based telescope, which is subject to poor seeing
Examples of objective evaluation
Galileo and Galilean Telescope
Reflecting Telescope
Einstein telescope.