Practice portal › Nuclei › Nuclear Reactions, Fission and Fusion

One of the fusion reaction in Sun is given by ²₁H+¹₁H→³₂He+γ+ ______ . Fill in the blank with correct option.

Asked in GSEB Board March 2023 · Energy released in fission and fusion

Answer: (2) 5.49 MeV

Step-by-step solution

Idea: the reaction printed is the third step of the proton-proton cycle — a deuteron captures a proton and becomes helium-3.

The steps of the cycle release, in order, 0.42 MeV, 1.02 MeV, 5.49 MeV and 12.86 MeV.

The one shown here, ²₁H+¹₁H→³₂He+γ, releases 5.49 MeV.

Check it against the total: with the first three steps happening twice each, 2(0.42+1.02+5.49)+12.86=26.7 MeV, the accepted net release per helium nucleus formed.

Why the other options are wrong

More Nuclear Reactions, Fission and Fusion questionsAll Nuclear Reactions, Fission and Fusion questions →

Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.

Practise this with a timer