The fuel used in an atomic pile is

Radioactivity is due to

In a nuclear explosion, the energy is released in the form of

Assertion : Nuclear binding energy per nucleon is in the order $_4^9Be > \,_3^7Li > \,_2^4He$.
Reason : Binding energy per nucleon increases linearly with the difference in the number of neutrons and protons.

Hydrogen can be fused to form helium at

For nuclear fusion reactions, the fusion temperature is of the order of