| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.36 |
| Score | 0% | 67% |
Absolute zero is which of the following?
the freezing point of hydrogen |
|
the coldest temperature possible in the universe |
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the freezing point of oxygen |
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0°C |
In contrast to the Celsius scale (measured in degrees centigrade) that fixes 0° at the freezing point of water and the Fahrenheit scale that uses 32°, the Kelvin scale fixes 0 at absolute zero (-273°C) which is the lowest temperature possible in the universe.
50°F is how many °C?
122 |
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10 |
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-10 |
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58 |
The formula to convert from F° to C° is:
\(C° = {5 \over 9} (F° - 32)\)
plugging in our values gives:
\(C° = {5 \over 9} (50 - 32)\)
\(C° = {5 \over 9} (18)\)
\(C° = {90 \over 9}\)
\(C° = 10\)
Generally, an atom has __________ negative electrons orbiting the nucleus as it does positive protons inside.
fewer |
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more |
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equal numbers of |
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double the number of |
An electron is a subatomic particle that orbits the nucleus of an atom. It carries a negative electric charge. Generally, an atom has the same number of negative electrons orbiting the nucleus as it does positive protons inside.
An endoskeleton (internal skeleton) is a charateristic of __________ animals, including humans.
sentient |
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arthropod |
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vertebrate |
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spiny |
An endoskeleton (internal skeleton) is a charateristic of vertebrate animals, including humans.
Veins __________ blood at __________ pressure.
deoxygenated, low |
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oxygenated, high |
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deoxygenated, high |
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oxygenated, low |
Veins carry blood back to the heart from the body. While arteries are thick-walled because they carry oxygenated blood at high pressure, veins are comparatively thin-walled as they carry low-pressure deoxygenated blood. Like the heart, veins contain valves to prevent blood backflow.