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

Options

A. 50% of its original number
B. 36.8% of its original number
C. 63.2% of its original number
D. 75% of its original number

Answer

B

Explanation

Number of atoms remains underyed, `N = N_(0)e^(-lamdat)`
`As, lamda=1/t" "("given")`
`impliesN=N_(o)e^(-lamda(1//lamda))=(N_(0))/(e)=36.8%of N_(0)`