Why can't radiations penetrate in lead, and how can aluminium foil block?

Radiations are high-energy electromagnetic waves that can penetrate through most materials. However, lead is an exceptional material that can block or absorb high-energy radiations such as x-rays and gamma rays. Lead is referred to as a dense metal due to its high atomic number, which means that it has a large number of protons in its nucleus. This dense atomic structure of lead makes it difficult for radiations to pass through it as the radiations get absorbed or deflected by the lead atoms.

Lead has been used for many years as a radiation shielding material. It is used in X-ray rooms, nuclear power plants, and other areas where radiation is present. The reason for this is that lead is an effective shield against high-energy radiation because of its dense atomic structure. It can stop or absorb the radiation before it gets a chance to affect living organisms or other materials. The thickness of lead required for radiation shielding depends on the energy of the radiation.

Aluminium foil, on the other hand, is a thin sheet made of aluminium metal. Unlike lead, which is an effective shield against high-energy radiations, aluminium foil can block low-energy radiations like alpha and beta particles. This is possible because aluminium has a low atomic number, which means that its atomic structure is less dense. Therefore, radiations can easily pass through it without getting absorbed or deflected. However, the thickness of the aluminium foil is sufficient to reduce the intensity of the radiation passing through it, making it an effective shield against low-energy radiations.

In conclusion, lead and aluminium foil have different properties that make them effective shields against radiation. Lead is an effective shield against high-energy radiations like x-rays and gamma rays due to its dense atomic structure, while aluminium foil can block low-energy radiations like alpha and beta particles due to its thickness and low atomic number.