Which of the following typically orbit within the disk of our galaxy?
A) stars of spectral types O and B
B) globular star clusters
C) the Large and Small Magellanic Clouds
D) other galaxies
A) stars of spectral types O and B
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Why do astronomers often measure the visible-light apparent brightness instead of the total apparent brightness of a star?
A) All stars put out most of their light in the visible range of the spectrum. B) In order to measure the total apparent brightness of a star, you must measure its brightness in all wavelengths, and this is difficult to do. The only wavelengths you can measure from the surface of Earth are visible and radio wavelengths. C) Most stars do not put out light in other ranges of the spectrum. D) They are identical for most stars. E) Astronomers are lazy.
The warming of the lower atmosphere (the greenhouse effect) results from the
A) absorption of long-wave solar radiation. B) reflection of long-wave terrestrial radiation. C) absorption of long-wave terrestrial radiation by atmospheric gases. D) release of atmospheric gases into the ozone layer.
When light reflects from a polished surface, there is a change in its
A) frequency. B) wavelength. C) speed. D) all of the above E) none of the above
Larger batteries have higher output voltages
Indicate whether the statement is true or false