SI Units Quiz

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Questions and Answers

What is the correct symbol for a unit named after the scientist Isaac Newton?

N (correct)

Which of the following units is written in lowercase letters?

Kilogram

Meter (correct)

Coulomb

Ampere

How should the unit symbol and the numeral be spaced?

No space should be left between them.

Two spaces should be left.

The numeral should follow immediately.

One space should be left. (correct)

Which of the following is incorrect regarding the plural forms of units?

Kilograms can be written as kgs. Signup and view all the answers

Which of these statements correctly describes how to format unit symbols?

No space should be used between symbols for units. Signup and view all the answers

What is the correct symbol for the unit of electric current, Ampere?

A Signup and view all the answers

What is the fundamental length unit in the CGS system of units?

centimeter Signup and view all the answers

Which of the following systems of units is known as the British system?

FPS system Signup and view all the answers

In the International System of Units (SI), which unit represents time?

second Signup and view all the answers

Which of the following stated rules is correct for writing SI units?

Full name of the unit always starts with a small letter. Signup and view all the answers

Which of the following is NOT a fundamental unit in the SI system?

inch Signup and view all the answers

What are the fundamental units in the MKS system of units?

metre, kilogram, second Signup and view all the answers

Which characteristic of units ensures that they can be replicated in any measurement?

Reproducible Signup and view all the answers

How many fundamental units are included in the SI unit system?

7 Signup and view all the answers

Which SI prefix corresponds to a factor of $10^{-3}$?

milli (m) Signup and view all the answers

What is the SI unit for length based on the meter?

centimeter (cm) Signup and view all the answers

In the MKS system, which of the following units is incorrect?

Liter for volume Signup and view all the answers

Which of the following is NOT an SI unit for measuring time?

Kelvin Signup and view all the answers

How many picometers are in a meter?

$10^{12}$ Signup and view all the answers

What is the primary use of the astronomical unit?

Measuring distances within the solar system Signup and view all the answers

According to the SI rules, how should units be written in terms of capitalization?

Units should be capitalized only when derived from proper names. Signup and view all the answers

Which of the following describes the FPS system of units?

Uses feet, pounds, and seconds as base units. Signup and view all the answers

Study Notes

Rules for Writing SI Units

Symbols for units named after scientists are capitalized: N for Newton, A for Ampere, K for Kelvin, C for Coulomb.
All other unit symbols are in lowercase: m for meter, kg for kilogram, s for second, cd for candela.
Leave one space between numerals and unit symbols, e.g., 10 kg, 5 N.
Units do not have plural forms: 6 meter is correct, not 6 meters.
No space between symbols for combined units, e.g., 4 J/s is correct, not 4 J s.

Characteristics of Units

Units must be well-defined, suitable in size, reproducible, invariable, indestructible, and internationally accepted.

Systems of Units

CGS System: Introduced in France, based on centimeter, gram, and second.
MKS System: Also French, using meter, kilogram, and second as fundamental units.
FPS System: British system based on foot, pound, and second.
SI System: Established in 1971, includes seven fundamental and two supplementary units.

Fundamental Units of SI

Length: metre (m)
Mass: kilogram (kg)
Time: second (s)
Temperature: kelvin (K)
Electric current: ampere (A)
Luminous intensity: candela (cd)
Amount of substance: mole (mol)

SI Prefixes

Prefixes indicate factors of ten, e.g., kilo (k) for 10^3, milli (m) for 10^-3, giga (G) for 10^9, and nano (n) for 10^-9.

Practical Examples of SI Units

Example conversions using prefixes:
- 3 milliampere = 3 mA = 3 × 10^-3 A
- 5 microvolt = 5 μV = 5 × 10^-6 V
- 8 nanosecond = 8 ns = 8 × 10^-9 s
- 6 picometre = 6 pm = 6 × 10^-12 m

Practical Units for Measuring Length

1 micron = 1 x 10^-6 m (used for bacteria).
1 nanometer = 1 x 10^-9 m (used for molecules).
Astronomical Unit: The mean distance of the Earth from the Sun, approximately 1.496 x 10^11 m.
Light Year: Distance light travels in one year, approximately 9.461 x 10^15 m.

Practical Units for Measuring Time

1 Solar day = 24 hours.
1 Sidereal day = 23 hours 56 minutes.
1 Solar year = 365 solar days = 366 sidereal days.
1 Lunar month = 27.3 solar days.
1 shake = 10^-8 seconds.

Example Conversions

10 meters to inches.
Speed in km/h to cm/s conversion.
1 kilometer to yards conversion.
18 kg to slugs.
432 to base conversion.
18.94 liters to gallons.
264 ft/s to miles per hour.
Height conversion from feet to centimeters.

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Description

Test your knowledge of the rules for writing SI units and the symbols for units named after scientists like Newton and Ampere. This quiz will help you understand the proper notation for these essential units in science. Perfect for students delving into physical sciences.