A _________ is one billionth of a metre.

The correct answer is nanometreKey Points

•  A nanometre is one billionth of a metre.
• It is often abbreviated as nm and is commonly used in fields such as physics, chemistry, and nanotechnology to measure extremely small lengths.

Additional Information

• P​arsec 
  • A parsec (abbreviated as pc) is a unit of distance used in astronomy.
  • It is equivalent to approximately 3.26 light-years or about 3.09 × 10^16 metres.
  •  Parsec is used to measure large distances to astronomical objects outside our solar system, such as stars and galaxies.
  • The term is derived from "parallax" and "arcsecond," reflecting how distances are determined using parallax measurements.
•  Micrometre
  •  A micrometre (abbreviated as µm) is a unit of length equal to one millionth of a metre (1 µm = 10^-6 m).
  •  Micrometres are commonly used in various scientific fields, including biology (to measure cells and microorganisms), materials science, and engineering.
  • For instance, the diameter of a human hair is about 70 to 100 micrometres.
• Angstrom
  • An angstrom (abbreviated as Å) is a unit of length equal to one ten-billionth of a metre (1 Å = 10^-10 m) or 0.1 nanometres.
  • Angstroms are primarily used in physics, chemistry, and materials science to measure atomic and molecular scales, such as the wavelengths of light and the sizes of atoms.
  • For example, the bond length between atoms in a molecule is typically measured in angstroms.