The phenomenon explained by tunnel effect is

• (A) β -decay
• (B) α -decay
• (C) γ -decay
• (D) All the above

The tunnel effect is a quantum phenomenon that allows particles to pass through potential barriers that they classically shouldn't be able to cross. This effect is particularly relevant in nuclear physics.

Which Decay Types Involve the Tunnel Effect?

Among the options provided:

• β-decay: Involves the transformation of a neutron into a proton, emitting an electron and an antineutrino. The tunnel effect plays a role here.
• α-decay: Involves the emission of an alpha particle from a nucleus. The tunnel effect is crucial for this process as the alpha particle must tunnel through the nuclear potential barrier.
• γ-decay: This type of decay involves the emission of gamma rays and does not typically involve tunneling.

Final Answer

Considering the above explanations, the correct answer is (D) All the above, as both β-decay and α-decay involve the tunnel effect, while γ-decay does not. However, the context of tunneling is primarily significant in the first two types.