Question

If Mo is the mass of an isotope, 178 O, Mp and Mn are the masses of a Proton and neutron respectively, the binding energy of the isotope is

(A) (Mo – 8Mp)C2

(B) (Mo – 8Mp – 9Mn)C2

(C) (Mo – 17Mn)C2

(D) MoC2

Answer 1

The correct option is (B) (Mo – 8Mp – 9Mn)C2.

Explanation:

Mo – mass of oxygen isotope 8O17.

Mp – mass of proton

Mn – mass of newtron

nuclear binding energy of isotope = Δm ∙ C2 ......(1)

Δm = mass defect

= difference between sum of masses of nucleons and atomic mass

Δm = (Mo) – [Zmp + (A – Z)mn]

Here Z = 8, A – Z = 17 – 8 = 9

∴ ΔM = Mo – (8Mp – 9Mn) = Mo – 8Mp – 9Mn

from (1)

BE = (Mo – 8Mp – 9Mn)C2.