Fusion processes like combining two deuterium nuclei to form a He nucleus are impossible at ordinary temperatures and pressures. The reason is:

(i) Nuclear forces are short range.

(ii) Original nuclei must first break before combining with other nuclei.

(iii) Nuclei is negatively charged.

(iv) Nuclei is positively charged.

1. only (i)
2. (i) and (ii)
3. (ii) and (iv)
4. (i) and (iv)

In the nuclear decay given below :

_ZX^A ⟶ _Z+1Y^A ⟶ _Z-1B^A-4 ⟶ _Z-1B^A-4

The particles emitted in the sequence are :

1. α, β, γ
2. β, α, γ
3. γ, β, α
4. β, γ, α

(a) Name the process, nuclear fission or nuclear fusion, in which the energy released per unit mass is more?

(b) Name the process, fission or fusion which is possible at ordinary temperature.