On some telescopes, actuators on the mirror change its shape to match distortions in the atmosphere. What is this technique called?
A. actuary observing
B. interferometry
C. adaptive optics
D. refraction
Answer: C
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Which of the following statements is true of the chromosphere?
A) It lies below the photosphere. B) It has a depth greater than Earth's diameter. C) It consists of nonionized atoms. D) It can be seen during a total solar eclipse.
Consider a magnifying glass with a power of 3.0 D
(a) What is the maximum magnification for a person with a near point of 25. cm? (b) What is the magnification when viewing with a relaxed eye?
Microscopes are inherently limited by the wavelength of the light used. How much smaller (in order of magnitude) can we "see" using an electron microscope whose electrons have been accelerated through a potential difference of 50 000 V than using red light (500 nm)?
a. 3 b. 4 c. 5 d. 6 e. 14
If body P, with a positive charge, is placed in contact with body Q (initially uncharged), what will be the nature of the charge left on Q?
a. must be equal in magnitude to that on P b. must be negative c. must be positive d. must be greater in magnitude than that on P