Question

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

Answer 1

Correct Answer - A
As `I=I_(0)e^(-mux)`
`:. 1/8e^(-mu.36) and 1/2=e^(-mux)`
`(1/2)^(3)=e^(-mu.36)=(e^(-mux)) or -3mux=-36mu`
`x=36/3 =12mm`