(a) What is the composition of α, β and γ radiations?

(b) Can a hydrogen ($_1^1\text{H}$) nucleus emit an alpha particle?

(c) Which one α, β and γ radiation has the least penetrating power?

(a) α radiation consists of two protons and two neutrons. β radiation is composed of fast moving electrons emitted from the nucleus of an atom while γ radiation is photon or electromagnetic waves like X-rays and light.

(b) No, hydrogen (${}_1^1\text{H}$1^1\text{H}) nucleus cannot emit an alpha particle because an alpha particle consists of two protons and two neutrons whereas hydrogen ($1^1\text{H}$) nucleus does not have two protons and two neutrons.

(c) α radiations have least penetrating power.