General Science: 50+ Most Important Scientific Units of Measurement

Question 1. Give three different units for temperature. Which is the SI unit?
Kelvin (K) is the SI unit for temperature. Others: Fahrenheit (°F) and Celsius (°C).
Note: we don’t use the degree (°) symbol for Kelvin because it is “absolute.”

Question 2. Give five different units for pressure. Which is the SI unit?
Pascal (Pa) is the SI unit for pressure, which equates to one N/m2.
Others: atmosphere (atm), bar (bar), pounds per square inch (psi), mm Mercury (mm Hg), torr (torr).

Question 3. Give two different units for heat. Which is the SI unit?
Joule (J) is the SI unit for heat. Others: calorie (cal), British thermal unit (Btu), electron Volt (eV), kilowatt hour (kWh), erg (erg), foot-pound (ft.·lb.).

Question 4. Give three different units for volume. Which is the SI unit?
Cubic meters (m3) are the SI units for volume. Others: cubic centimeters (cc), liters (L), cubic feet (ft.3), gallon (gal).

Question 5. What is the SI unit for weight? What is the British unit for weight?
Newton (N) is the SI unit for weight. Pound (lb.) is the British unit for weight.

Question 6. What is the SI unit for mass? What is the British unit for mass?
Kilogram (kg) is the SI unit for mass. Slug (slug) is the British unit for mass.

Question 7. Which unit is defined such that 12C has a mass exactly equal to 12 in that unit?
Atomic mass unit (amu) is defined such that 12C has a mass equal to 12 amu.

Question 8. Which unit is equal to kg m/s2? Which unit (that includes no prefix) is equal to g cm/s2?
One Newton (N) equals kg m/s2. One dyne (dyne) equals g cm/s2.

Question 9. Give two different units for angle. Which is required in the formula for arc length?
Radian (rad) is required in the formula for arc length. Other: degree (°).

Question 10. What are the SI units for acceleration?
Meter per square second (m/s2) are the SI units for acceleration.

Question 11. Give three different units for energy. Which is the SI unit?
Joule (J) is the SI unit for energy. Others: calorie (cal), British thermal unit (Btu), electron Volt (eV), kilowatt hour (kWh), erg (erg), foot-pound (ft.·lb.).

Question 12. What is the SI unit for power? How is it related to the SI unit for work?
Watt (W) is the SI unit for power. One Watt equals one Joule per second (J/s).

Question 13. What are the SI units for density?
Kilogram per cubic meter (kg/m3) are the SI units for density.

Question 14. Which unit is defined as the average distance from the earth to the sun?
One astronomical unit (AU) is equal to the average earth-sun distance.

Question 15. Which unit is defined as the distance that light travels in one year?
One light-year (ly) is the distance that light travels in one year.

Question 16. Which unit is approximately 3.26 times as large as the answer to Question 15?
One parsec (parsec) is approximately equal to 3.26 light-years.

Question 17. What is the SI unit for period? What is the SI unit for frequency?
Second (s) is the SI unit for period. Hertz (Hz) is the SI unit for frequency.
Note: one Hertz (Hz) is equal to an inverse second (s–1).

Question 18. Which physical quantity may be expressed with the units kWh?
Energy (or work) may be expressed with the units kWh (but not power).
Note: Although power is measured in Watts, note that kWh is different because it multiplies by hours (h).

Question 19. Give two different units for enthalpy. Which is the SI unit?
Joule (J) is the SI unit for enthalpy. Others: calorie (cal), British thermal unit (Btu), electron Volt (eV), kilowatt hour (kWh), erg (erg), foot-pound (ft.·lb.).

Question 20. What are the SI units for entropy?
Joules per Kelvin (J/K) are the SI units for entropy.

Question 21. Give the SI units for any (your choice) variety of heat capacity or specific heat capacity.
The common units are J/(kg K) for specific heat or J/(mol K) for molar specific heat. (For the broad definition of “heat capacity,” i.e. not specific, you would get J/K, but almost all problems involve specific heat or molar specific heat.)

Question 22. What is the SI unit for electric charge?
Coulomb (C) is the SI unit for electric charge. It’s equivalent to A·s.

Question 23. What is the SI unit for electric current?
Ampère (A) is the SI unit for electric current. It’s equivalent to C/s.

Question 24. What is the SI unit for capacitance?
Farad (F) is the SI unit for capacitance.

Question 25. What is the SI unit for resistance?
Ohm is the SI unit for resistance.

Question 26. What is the SI unit for electric potential or for potential difference?
Volt (V) is the SI unit for electric potential and for potential difference.

Question 27. What are the SI units for electric field? (Bonus for two equivalent answers.)
Newton per Coulomb (N/C), equivalent to Volt per meter (V/m), are the SI units for electric field.

Question 28. What is the SI unit for magnetic field?
Tesla (T) is the SI unit for magnetic field. Note: Gauss (G) is not the SI unit.

Question 29. What are the SI units for Planck’s constant?
Joule times second (J·s) are the SI units of Planck’s constant. It’s equivalent to J/Hz.

Question 30. What are the SI units for the gravitational constant in Newton’s law of gravity?
N m2/kg2 are the SI units for the gravitational constant. It’s equivalent to m3/(kg s2).
Note: Question 30 asks for the units of G, whereas Question 31 asks for the units of g.

Question 31. What are the SI units for gravitational acceleration?
Meter per square second (m/s2) are the SI units for gravitational acceleration.

Question 32. What are the SI units for Coulomb’s constant?
N m2/C2 are the SI units for Coulomb’s constant. It’s equivalent to kg m3/(C2 s2).

Question 33. What are the SI units for momentum?
Kilogram times meter per second (kg·m/s) are the SI units for momentum. It’s equivalent to a Newton times a second (N·s).

Question 34. What are the SI units for impulse?
Newton times second (N·s) are the SI units for impulse. It’s equivalent to the SI units for momentum, kg·m/s.

Question 35. What are the SI units for torque?
Newton times meter (N·m) are the SI units for torque, but not just Newton (N).

Question 36. What are the SI units for moment of inertia?
Kilogram times square meter (kg·m2) are the SI units for moment of inertia.

Question 37. What are the SI units for angular momentum?
Kilogram times square meter per second (kg·m2/s) are the SI units for angular momentum.

Question 38. What is the SI unit for the coefficient of friction?
None. Trick question: the coefficient of friction is unitless.

Question 39. What is the SI unit for friction force?
Newton (N) is the SI unit for friction force (or any other kind of force).

Question 40. What is the SI unit for loudness?
Decibel (dB) is the SI unit for loudness.

Question 41. What is the SI unit for wavelength?
Meter (m) is the SI unit for wavelength (or any other kind of distance).

Question 42. What is the SI unit for index of refraction?
None. Trick question: the index of refraction is unitless.

Question 43. Which base SI unit is used for luminous intensity?
Candela (cd) is the base SI unit used for luminous intensity.

Question 44. What are the SI units for electric flux?
N m2/C are the SI units for electric flux. It’s equivalent to kg m3/(C s2) or V·m.

Question 45. What are the SI units for magnetic flux?
The weber (Wb), or equivalently Tesla times square meter (T·m2), is the SI unit for magnetic flux. It’s also equivalent to V·s.

Question 46. What is the SI unit for half-life?
Second (s) is the SI unit for half-life (or any other kind of time).

Question 47. Which quantity may be expressed with units of eV?
Work or energy may be expressed with units of eV.

Question 48. Which symbol is written after the number for the magnification of a lens?
The times symbol (×) is written after the number for the magnification of a lens. For example, a telescope might have a magnification of 50×.

Question 49. What are the SI units for the universal gas constant?
J/(mol K) are the SI units for the universal gas constant. (In some contexts it is convenient to work with other units, but these are the SI units.)

Question 50. What are the SI units for body mass index?
Kilograms per square meter (kg/m2) are the SI units for body mass index.

Question 51. What is the SI unit for inductance?
Henry (H) is the SI unit for inductance. It’s equivalent to

Question 52. What is the SI unit for the work function of a metal?
Joule (J) is the SI unit for the work function of a metal (or any other kind of work).

Question 53. What are the SI units for the Stefan-Boltzmann constant?
W/(m2 K4) are the SI units for the Stefan-Boltzmann constant (lowercase sigma).

Question 54. What are the SI units for Boltzmann’s constant?
Joule per Kelvin (J/K) are the SI units for Boltzmann’s constant (kB).

Question 55. What is the SI unit for radioactivity?
Becquerel (Bq) is the SI unit for radioactivity.