Explain `alpha`- decay ?

Define alpha decay?

In an alpha -decay

Explain gamma - decay ?

Explain beta - decay ?

Write the application of alpha decay in smoke detectors.

During alpha -decay:

During alpha -decay:

During alpha -decay:

How do the mass number and atomic number change in alpha -decay? A nucleus X becomes nucleus Y as a result of alpha -decay. Represent it by an equation.