What is Roentgen (unit)?
The '''roentgen''' or '''röntgen''' is a unit of measurement for the exposure of [[X-ray|X-rays]] and [[Gamma ray|gamma rays]]. It is defined as the [[electric charge]] freed by such radiation in a specified volume of air divided by the mass of that air. It is named after the German physicist [[Wilhelm Röntgen]], who discovered [[X-ray|X-rays]]. {{physics-stub}} [[Category:Units of measurement]]