We know that the central object in a planetary nebula has a surface temperature of at least ____ because the nebula contains large amounts of ionized hydrogen
a. 50 K
b. 100 K
c. 500 K
d. 5,000 K
e. 25,000 K
e
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Which of the following is not caused by the Coriolis effect on Earth?
A) Water going down a drain swirls in opposite directions in the Northern and Southern hemispheres. B) Earth's global circulation cells are split into three separate cells in each hemisphere. C) Hurricanes swirl in opposite directions in the Northern and Southern hemispheres. D) Air or objects moving northward in the Northern Hemisphere are deflected to the east.
The eye focuses by
A. moving the lens. B. moving the retina. C. moving both the lens and the retina. D. changing the focal length of the lens. E. changing the index of refraction of the vitreous fluid.
We can see most of the galaxy with visible light
Indicate whether the statement is true or false
Two iron bars are on the laboratory table. They are identical in every respect except that one is a magnet and the other is not. Without using anything other than the two iron bars, explain how you could identify the magnet