# NEET Physics Nuclei Questions Solved

In a sample of radioactive material, what fraction of the initial number of active nuclei will remain undisintegrated after half of a half-life of the sample
(a) $\frac{1}{4}$        (b) $\frac{1}{2\sqrt{2}}$
(c) $\frac{1}{\sqrt{2}}$     (d) $2\sqrt{2}$