| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.60 |
| Score | 0% | 72% |
The rows of the Periodic Table of the Elements are called:
families |
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periods |
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shells |
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groups |
The rows of the Periodic Table are called periods and contain elements that have the same number of electron shells ordered from lower to higher atomic number.
The pitch of the siren of an approaching ambulance changes as it approaches you. This is an example of which of the following?
sound radiation |
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refraction |
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Doppler effect |
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reflection |
The Doppler effect occurs when the source or listener (or both) of sound waves is moving. If they're moving closer together, the listener perceives the sound with a higher pitch and, when they're moving apart, the listener perceives the sound with a lower pitch.
The Sun is a __________-type main-sequence star.
G |
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E |
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D |
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S |
The Sun is a G-type main-sequence star (G2V) but is informally known as a yellow dwarf star. Composed of 73% hydrogen and 25% helium, the hot plasma that makes up the Sun reaches 9,900°F (5,505°C) at the surface. It formed approximately 4.6 billion years ago and makes up 99.86% of the mass in the solar system.
A subatomic particle found in the nucleus of an atom. It carries no electric charge. This desribes which of the following?
atom |
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proton |
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electron |
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neutron |
A neutron is a subatomic particle found in the nucleus of an atom. It is neutral as it carries no electric charge.
Which of the following describes the Earth's mantle?
dense |
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all of these |
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makes up most of Earth's volume |
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hot |
Mantle makes up 84% of the Earth's volume and has an average thickness of approximately 1,800 miles (2,900 km). It is dense, hot, and primarily solid although in places it behaves more like a viscous fluid as the plates of the upper mantle and crust gradually "float" along its circumference.