Using a nuclear counter the count rate of emitted particles from a radioactive source is measured. At t=0 it was 1600 counts per second and t = 8 seconds it was 100 counts per second. The count rate observed, as counts per seconds, at t=6, seconds is close to :

Options

A. 150
B. 200
C. 360
D. 400

Answer

B

Explanation

`a=A_(0)e^(-lamdat)`
`100=1600e^(-lamda8)rArr1/16=e^(-lamda8)rArre^(-lamda)=(1/16)^(1/8)`
`A_(at6s)=1600e^(-lamda6)=1600(e^(-lamda))^(6)=1600(1/16)^(3/4)=1600(1/(2^(4)))^(3/4)=1600/8=200`