inverse square law

American  

noun

Physics, Optics.

1. one of several laws relating two quantities such that one quantity varies inversely as the square of the other, as the law that the illumination produced on a screen by a point source varies inversely as the square of the distance of the screen from the source.

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inverse square law British  

noun

1. any natural law in which the magnitude of a physical quantity varies inversely with the square of the distance from its source

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inverse-square law Scientific  

1. The principle in physics that the effect of certain forces on an object varies by the inverse square of the distance between the object and the source of the force. The magnitude of light, sound, and gravity obey this law, as do other quantities. For example, an object placed three feet away from a light source will receive only one ninth (1/3², the inverse of 3 squared) as much illumination as an object placed one foot from the light.

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Example Sentences

Once you measure a Cepheid’s period, you can calculate its distance from how bright it appears using the inverse square law.

From Salon • Feb. 14, 2025

The researchers found that all the unique choices people make—from dropping kids at school to shopping or commuting—obey this inverse square law when considered in aggregate.

From Scientific American • Oct. 7, 2021

Using the inverse square law for light, estimate the luminosity of 3C 273 in solar units.

From Textbooks • Oct. 13, 2016

On this small-scale, do gravitational effects depart from the inverse square law?

From Textbooks • Aug. 12, 2015

This outward force would balance the force of the Earth’s gravity if gravity fell off in accordance with an inverse square law, but Newton did not explicitly state this at the time.

From "The Scientists" by John Gribbin