Question

The type of reactions considered to be the principal sources of energy in stars is _____ when hydrogen is converted to helium.

• A. nuclear fission
• B. nuclear fusion
• C. radioactive decay
  
• D. none of the above

Answer 1

The correct option is B nuclear fusion

The type of reactions considered to be the principal sources of energy in stars is Fusion when hydrogen is converted to helium. Such reactions occur at very high temperature $(>{10}^{6}K)$ with the release of a huge amount of energy in the form of nuclear energy. The energy is released due to mass defect.
$4_1^{1}H{\stackrel{Fusion}{\to }}_2^{4}He+2_1{e}^0+energy$