The intensity of gamma radiation from a given source is `I`
On passing through `36 mm` of lead , it is reduced to `(1)/(8)` . The thickness of lead which will reduce the intensity to `(1)/(2)` will be

Options

A. 12 mm
B. 18 mm
C. 9 mm
D. 6 mm

Answer

A

Explanation

As `I=I_(0)e^(-mux)`
`therefore (1)/(8)=e^(-mu36) and (1)/(2)=e^(-mux)`
`((1)/(2))^(3)=e^(-mu36)`
`or e^(-3mux)=e^(-mu36) or x=(36)/(3)="12 nm"`