State whether the following statements are true or false: If false, correct the statement.
Einstein’s theory of mass-energy equivalence is used in nuclear fission and fusion.

Arrange in descending order, on the basis of their penetration power.
Alpha rays, Beta rays, Gamma rays, Cosmic rays.

Arrange the following in the chronological order of discovery.
A nuclear reactor, Radioactivity, Artificial radioactivity, Discovery of radium.

Use the analogy to fill in the blank.

Spontaneous process: Natural Radioactivity, Induced process: _____.