Nuclei - Result Question 93
95. The mass of $\alpha$-particle is
[1992]
(a) less than the sum of masses of two protons and two neutrons
(b) equal to mass of four protons
(c) equal to mass of four neutrons
(d) equal to sum of masses of two protons and two neutron
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Answer:
Correct Answer: 95. (a)
Solution:
- (a) $\alpha$-particle $= _2 He^{4}$. It contains $2 p$ and $2 n$. As some mass is converted into B.E., therefore, mass of $\alpha$ particle is slightly less than the sum of the masses of $2 p$ and $2 n$.
(d) $\frac{N}{N_0}=(\frac{1}{2})^{6400 / 1600}=(\frac{1}{2})^{4}=\frac{1}{16}$
