Converting Angstroms to Nanometers

This example problem demonstrates how to convert angstroms to nanometers. Angrstroms (Å) and nanometers (nm) are both linear measurements used to express extremely small distances.

Problem:

The spectra of the element mercury has a bright green line with a wavelength of 5460.47 Å. What is the wavelength of this light in nanometers?

Solution:

1 Å = 10^-10 m
1 nm = 10^-9 m

Set up the conversion so the desired unit will be cancelled out. In this case, we want nanometers to be the remaining unit.

wavelength in nm = (wavelength in Å) x (10^-10 m/1 Å) x (1 nm/10^-9 m)
wavelength in nm = (wavelength in Å) x (10^-10/10^-9 nm/Å)
wavelength in nm = (wavelength in Å) x (10^-1) nm/Å)
wavelength in nm = (5460.47/10) nm
wavelength in nm = 546.047 nm

Answer:

The green line in mercury's spectra has a wavelength of 546.047 nm.

It may be easier to remember there are 10 angstroms in 1 nanometer. This would mean that 1 angrstrom is a tenth of a nanometer and a conversion from angrstroms to nanometers would mean moving the decimal place one position to the left.