Question

The half life of a radioactive material is T. after T/2 time, the material left is :-

• A. 1/2
• B. 3/4
• C. $\frac{1}{\sqrt{2}}$
• D. $(\sqrt{2}-1)/\sqrt{2}$

Answer 1

Answer: (C)

$\frac{1}{\sqrt{2}}$

Given,

$T=$ half life time of a radioactive material

$t=\frac{T}{2}$

The fraction of the material is,

$\frac{N}{N_0}=[\frac{1}{2}{]}^{t/T}$

$\frac{N}{N_0}=[1/2{]}^{\frac{T/2}{T}}=\frac{1}{\sqrt{2}}$

The correct option is C.