Units and measures quiz
Checked on 4 November 2026
Question 1 of 10
Discover
Which unit is the SI base unit for temperature?
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The answer is Kelvin.
The kelvin (symbol K) is the base unit for temperature in the International System of Units. It is named after Lord Kelvin.
Discover
In the word "millimetre", what does the prefix milli mean?
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The answer is One thousandth.
Milli stands for 10 to the power of minus 3, so a millimetre is one thousandth of a metre.
Discover
A speed of one knot means one nautical mile per what?
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The answer is Hour.
The knot is a unit of speed equal to one nautical mile per hour, which is exactly 1.852 km/h.
Discover
Which unit measures electrical resistance?
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The answer is Ohm.
The ohm is the SI unit of electrical resistance. It is named after the German physicist Georg Ohm.
Practise
The international nautical mile is defined as exactly how many metres?
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The answer is 1,852 metres.
The international nautical mile is exactly 1,852 metres, a little longer than a land mile.
Practise
Which SI unit measures luminous intensity?
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The answer is Candela.
The candela (symbol cd) is the SI unit of luminous intensity and one of the seven SI base units.
Practise
How many base units does the International System of Units (SI) have?
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The answer is Seven.
The SI uses seven base units: the second, metre, kilogram, ampere, kelvin, mole and candela.
Expert
An imperial gallon is defined as exactly how many litres?
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The answer is 4.54609 litres.
The imperial gallon is exactly 4.54609 litres, while the smaller US gallon is 231 cubic inches, about 3.785 litres.
Expert
In 2022, two new metric prefixes for very large multiples were adopted. One was ronna; what was the other?
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The answer is Quetta.
Ronna (10 to the power of 27) and quetta (10 to the power of 30) were added in 2022, alongside ronto and quecto for tiny fractions.
Expert
The tesla is the SI unit of which quantity?
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The answer is Magnetic flux density.
The tesla (symbol T) measures magnetic flux density, also called the magnetic B-field. It honours the engineer Nikola Tesla.