What causes the outward gas pressure that balances the inward pull of gravity in a main-sequence star?
a. the rapid outward flow of gas
b. the rapid inward flow of the gas
c. the high temperature of the gas
d. the high density of the gas
e. the high temperature and the high density of the gas
Answer: e. the high temperature and the high density of the gas
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An eyeglass lens is cut with one surface having a radius R1 and the other surface having a radius R2, with R1 < R2 . Both positive radii are measured from the same side with R1 being the side closer to the eye. Is this convex-concave lens a converging lens or a diverging lens?
a. This is a converging lens. b. This is a diverging lens. c. This can be either a converging or diverging lens, as more information is needed for a final determination. d. This is neither, since a lens cannot be made this way.
What is Jupiter's Great Red Spot?
A) a giant storm that is about twice as wide as the planet Earth B) a giant crater on the surface of Jupiter C) a portion of strongly heated gas near the surface of Jupiter caused by a collision with a comet D) a huge patch of sulfur in Jupiter's atmosphere E) reflected sunlight that is red for the same reason sunrises and sunsets are red on Earth
A hydrogen atom that emits an alpha particle is a routine occurrence in
A) the environment. B) laboratories. C) unlikely. D) impossible.
On the scale of the cosmic calendar, in which the history of the universe is compressed to 1 year, when did the Sun and Earth form?
A) January B) December C) September D) February