The decay constant of a radioactive substance is` 0.173 year^(-1)`. Therefore,

Options

A. Nearly 63% of the radioactive substance will decay in (1/0.173) year.
B. half life of the radio active substance is (1/0.173) year.
C. one-fourth of the radioactive substance will be left after nearly 8 years.
D. one-fourth of the radioactive substance will be left after nearly 6 years.

Explanation

Given `lambda=0.173`
`T_(1//2)=(ln2)/(lambda)=0.693/0.173~=4`
Also for t 1/0.173 year
Remaining nuclei `N=N_(0)e^(-1)=0.37 N_(0)`
Decay nuclie=`N_(0)-N=0.63 N_(0)`