Physicists have greatly helped in finding the age of an object by the Carbon-14
(a) All living things, like plants and animals contain radioactive carbon called Carbon-14.
(b) Living things absorb the same amount of Carbon-14 from the atmosphere as they loose through radioactivity.
(c) After death, the body continues to lose Carbon-14 but stops to absorb it from the atmosphere.
(d) By finding out the Carbon-14 content of an object, it can be said as to how old an object is.