How many times will the intensity of a narrow `X`-ray beam of wavelength `20pm` decrease after passing through a lead plate of thickness `d = 1.0 mm` if the mass absorption coefficient for the given radiation wavelength is equal to `mu//rho = 3.6 cm^(2)//g`?

Explanation

The transmission factor is `e^(-mu d)` and so the intensity will decrease
`e^(mu d)`
`=e^(3.6 xx 11.3 xx 0.1) = 58.4` timestimes
(we have used `mu = (mu//rho) xx rho` and used the known value of density of lead).