What types of observations are necessary to determine the absolute luminosity of a star?
What will be an ideal response?
The absolute luminosity of a star, or absolute magnitude, is determined from the apparent magnitude and distance. The apparent magnitude is rather easily measured using a telescope and a photometer. The distance can be much harder to determine. If the star is nearby then its parallax can be measured. If more distant, some other method will have to be used, such as spectroscopic parallax. Spectroscopic parallax will give the absolute magnitude of the star without having to compute distance.
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What is true of the lunar highlands?
A) They are less heavily cratered than the mare. B) They are the darker regions of the Moon seen with the naked eye. C) They are found on the Moon's northern hemisphere. D) They are younger than the darker mare. E) They are the oldest part of the lunar surface.
The speed of a wave pulse on a string depends on the tension, F, in the string and the mass per unit length, ?, of the string
Tension has SI units of and the mass per unit length has SI units of What combination of F and ? must the speed of the wave be proportional to? A) F / ? B) ? / F C) D) E)
When light goes from one material into another material having a HIGHER index of refraction
A) its speed, wavelength, and frequency all decrease. B) its speed and wavelength decrease, but its frequency stays the same. C) its speed decreases but its wavelength and frequency both increase. D) its speed decreases but its frequency and wavelength stay the same. E) its speed increases, its wavelength decreases, and its frequency stays the same.
Sketch the circuit or network between four opaque body surfaces.
What will be an ideal response?