Q-value of nuclear reactions — UPSC Physics Optional CSE 1998 Paper II

What is the basis of thermonuclear fusion? Estimate the order of temperatures required for promoting the fusion reaction of lighter nuclei. Calculate the Q-value of the proton-proton cycle. 4 {}_1^1 H \rightarrow {}_2^4 He + 2 {}_{+1}^0 e + Q.