Suppose you want to know the chemical composition of a distant star. Which piece of information is most useful to you?
A) The peak energy of the star's thermal radiation.
B) The Doppler shift of the star's spectrum.
C) The wavelengths of spectral lines in the star's spectrum.
D) Whether the star's spectrum has more emission lines or more absorption lines.
C
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Compared with the period of satellites in close Earth orbit, the period of satellites orbiting far from Earth is
A) shorter. B) the same. C) longer. D) need more information
A key is placed in a hot oven and warmed to 100°C. As a result
a. the hole in the key becomes smaller. b. the key is bent into an arc. c. the key becomes longer. d. all of the above.
How much energy is carried by a photon of light having frequency 110 GHz? (h = 6.626 × 10-34 J ? s)
A) 1.1 × 10-20 J B) 1.4 × 10-22 J C) 7.3 × 10-23 J D) 1.3 × 10-25 J
A thin ribbon of a silver alloy 2.00-cm wide and 0.0150-mm thick carries a current of 6.98 A perpendicular to a magnetic field. The Hall voltage is found to be 1.24 × 10?4 V when the magnetic field is 2.50 T. Calculate n, the number of charge carriers per cubic meter.
What will be an ideal response?