X-Ray Absorption: 0.7cm Bone Thickness | Homework Help

[Jimmy87]

Homework Statement

A radiographer in a hospital directs a parallel beam of X-Rays at the leg bone of a patient. The attenuation coefficient of bone is 0.7cm^-1.

To 1 sig fig. what is the intensity of X-Rays transmitted through bone of thickness 0.7cm?

Homework Equations

I = I₀e^-μx

Where I is transmitted intensity, I₀ is original intensity, μ is attenuation coefficient and x is thickness.

The Attempt at a Solution

This is a multiple choice question and the answer is 40%. I’m pretty sure this answer is wrong. I got 60% - could someone confirm? Or have I made a silly mistake?

Thanks

 

[kuruman]

I also get 60%. The answer, 40%, is the absorbed intensity.