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

Options

A. Nearly `63%` of the radioactive sustance will decay in `(1//0.173)` year
B. Half life of the radio active substance is `(1//0.173)` years
C. One-fourth of the radioactive substance is `(1//0.173)` years
D. All the above statements are true

Answer

A, C

Explanation

`lambda=0.173, N=N_(0) e^(-lambdat)`
`DeltaN=(N_(0) -N_(0)e^(-lambdat))=` Decayed amount
`DeltaN=N_(0) (1-1/e)`
`DeltaN=N_(0)(1-0.37)=N_(0) (0.63)`
`(Delta N)/N_(0)=[(N_(0)(0.63))/N_(0)]xx100=63%`
`T_(1//2)=(log_(e)2)/(lambda)=4` year