Physics quiz
Checked on 11 November 2026
Question 1 of 10
Discover
What is the SI unit of force?
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The answer is Newton.
The newton is the unit of force, and one newton speeds up a 1 kg mass by one meter per second every second.
Discover
At normal sea-level air pressure, water boils at about what temperature?
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The answer is 100 °C.
On the Celsius scale water freezes at 0 °C and boils at about 100 °C at standard air pressure.
Discover
What happens when the north pole of one magnet is brought near the south pole of another?
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The answer is They attract.
Opposite poles attract and like poles repel, which is why north and south pull together.
Discover
Which SI unit is used to measure energy?
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The answer is Joule.
The joule is the SI unit of energy, work and amount of heat.
Practise
The watt is the SI unit of which quantity?
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The answer is Power.
The watt measures power, and one watt equals one joule per second.
Practise
What does the hertz measure?
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The answer is Frequency.
The hertz is the SI unit of frequency, equal to one cycle per second.
Practise
Newton's third law says that when one object pushes on another, the second object pushes back with a force that is...
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The answer is Equal and opposite.
When two objects exert forces on each other, the forces have the same size but point in opposite directions.
Expert
Newton's first law of motion is also known as the law of what?
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The answer is Inertia.
The first law says an object stays at rest or keeps moving in a straight line at constant speed unless an unbalanced force acts on it, which is inertia.
Expert
Absolute zero, or 0 kelvin, is equal to what temperature in degrees Celsius?
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The answer is -273.15 °C.
Absolute zero is the coldest possible temperature, 0 K, which is -273.15 °C or -459.67 °F.
Expert
The speed of light in a vacuum is defined as exactly how many meters per second?
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The answer is 299,792,458.
The SI fixes the speed of light in a vacuum at exactly 299,792,458 meters per second, roughly 300,000 km every second.