Why do population II stars contain almost nothing but hydrogen and helium?
What will be an ideal response?
This first generation of stars must be made of the elements produced in primordial nucleosynthesis, which had time only to turn 25% of the hydrogen into helium.
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The orbits of most comets:
A) are like the planets, fairly circular and in the ecliptic plane. B) lie almost entirely beyond the orbit of Neptune. C) have perihelions within the orbits of Mercury. D) go no farther out than Pluto, then return to the Sun again. E) are shorter than the 76 year period for Comet Halley.
According to the law of poles, like poles ______________
Fill in the blank(s) with correct word
The transmitted intensity of an unpolarized beam of light passing through a polarizer is one half of the value of the original intensity
Indicate whether the statement is true or false
Force on a Wire: A rectangular coil, with corners labeled ABCD, has length L and width w. It is placed between the poles of a magnet, as shown in the figure. If there is a current I flowing through this coil in the direction shown, what is the direction of the force acting on section CD of this coil?
A. perpendicular to and into the page B. perpendicular to and out of the page C. in the direction of the magnetic field D. in the opposite direction of the magnetic field E. The force is zero.