# NEET Physics Nuclei Questions Solved

Radioactive material A has decay constant 8$\lambda$ and material B has decay constant $\lambda$ Initially, they have same number of nuclei. After what time, the ratio of number of nuclei of material B to that A will be $\frac{1}{e}$?

(a) $\frac{1}{\lambda }$

(b) $\frac{1}{7\lambda }$

(c) $\frac{1}{8\lambda }$

(d)$\frac{1}{9\lambda }$