Questions on SI Base Units
Multiple-Choice Questions – SI Base Units
1. Which of the following is the SI base unit for length?
A) Gram
B) Meter
C) Liter
D) Foot
E) Inch
2. The SI base unit for mass is:
A) Newton
B) Gram
C) Pound
D) Kilogram
E) Tonne
3. Which SI base unit is used to measure time?
A) Minute
B) Hour
C) Second
D) Millisecond
E) Clock
4. The SI base unit for temperature is:
A) Degree Celsius
B) Fahrenheit
C) Kelvin
D) Calorie
E) Joule
5. What is the SI base unit of electric current?
A) Volt
B) Ampere
C) Watt
D) Coulomb
E) Ohm
6. The SI base unit for amount of substance is:
A) Mole
B) Gram
C) Atom
D) Liter
E) Molecule
7. Which of the following is the SI base unit for luminous intensity?
A) Lux
B) Candela
C) Lumen
D) Candle
E) Watt
8. How many SI base units are there in the International System of Units?
A) 5
B) 6
C) 7
D) 8
E) 9
9. Which base unit is abbreviated as "mol"?
A) Molecule
B) Mole
C) Millimole
D) Molecular unit
E) Molecular mass
10. The SI base unit "A" stands for:
A) Ampere
B) Atom
C) Area
D) Angstrom
E) Arcminute
11. Which physical quantity does the kilogram represent?
A) Time
B) Force
C) Mass
D) Weight
E) Density
12. The meter is defined based on:
A) The length of a metal rod
B) The Earth’s circumference
C) The distance light travels in a vacuum in a specific time
D) Human height average
E) The length of a pendulum
13. The Kelvin scale begins at:
A) 0°C
B) −273.15°C
C) 273.15°C
D) 100°C
E) 1°C
14. Which of the following quantities is NOT associated with an SI base unit?
A) Velocity
B) Time
C) Mass
D) Electric current
E) Length
15. What unit would be used to measure the brightness of a light source?
A) Lux
B) Joule
C) Ampere
D) Candela
E) Watt
16. Which SI base unit is used in chemistry to express the amount of substance?
A) Liter
B) Mole
C) Gram
D) Volume
E) Density
17. The second is currently defined by:
A) The Earth's rotation
B) Pendulum swings
C) Oscillations of a cesium atom
D) Stopwatch accuracy
E) Solar time
18. Which of the following is not a base unit in SI?
A) Meter
B) Second
C) Gram
D) Mole
E) Kelvin
19. What is the base unit for measuring electrical flow?
A) Volt
B) Ohm
C) Ampere
D) Watt
E) Joule
20. Why is the kilogram, and not the gram, the SI base unit for mass?
A) It's easier to measure
B) It’s based on the weight of water
C) The SI system prefers larger numbers
D) It's the historical standard
E) Definitions are based on constants using the kilogram
- Questions on Chemical Symbols and Formulas
- Questions on Chemical Properties
- Questions on Reactants and Products
Answer Key with Explanations
1. B) Meter
The SI base unit for length is the meter (m).
2. D) Kilogram
The SI base unit for mass is the kilogram (kg).
3. C) Second
Second (s) is the base unit for time.
4. C) Kelvin
The Kelvin (K) is the SI base unit for temperature.
5. B) Ampere
Ampere (A) is the base unit for electric current.
6. A) Mole
Mole (mol) is the unit for the amount of substance.
7. B) Candela
Candela (cd) is the SI base unit for luminous intensity.
8. C) 7
There are 7 SI base units.
9. B) Mole
"mol" is the abbreviation for mole.
10. A) Ampere
"A" stands for ampere, the unit of electric current.
11. C) Mass
Kilogram measures mass.
12. C) The distance light travels in a vacuum in a specific time
A meter is based on how far light travels in 1/299,792,458 seconds.
13. B) −273.15°C
Kelvin starts at absolute zero, equivalent to −273.15°C.
14. A) Velocity
Velocity is a derived unit, not a base unit.
15. D) Candela
Candela measures the brightness (luminous intensity).
16. B) Mole
Mole is used in chemistry for the amount of substance.
17. C) Oscillations of a cesium atom
The second is defined using cesium-133 atom oscillations.
18. C) Gram
Gram is not an SI base unit; the base is kilogram.
19. C) Ampere
Ampere is the unit of electrical current (flow).
20. E) Definitions are based on constants using the kilogram
The kilogram is now defined using the Planck constant, making it the official SI base.
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