Question

The masses of ¹¹C and ¹¹B are respectively 11.0114 u and 11.0093 u. Find the maximum energy a positron can have in the β⁺-decay of ¹¹C to ¹¹B.

Answer 1

''C →''B +β⁺+  v

mass of C'' = 11.014u ; mass of B'' = 11.0093u

Energy liberated = (11.014 – 11.0093)u = 29.5127 Mev.

For maximum K.E. of the positron energy of v may be assumed as 0.

Maximum K.E. of the positron is 29.5127 Mev.