g At 4 ft. from a point source of gamma radiation the intensity is 158 mRem/hr. How far away would you have to move to decrease the intensity to 17 mRem/hr.? [I1/I2 = (D2)2/(D1)2] I1(D1)2 = I2(D2)2

You will have to move 12.2 ft to decrease the initial intensity to 17 mRem/h.

Explanation:

The distance can be calculated using the following equation:

Where:

I₁ = 158 mRem/h

I₂ = 17 mRem/h

D₁ = 4 ft.

D₂=?

Hence, the distance D₂ is:

Therefore, you will have to move 12.2 ft to decrease the initial intensity to 17 mRem/h.

I hope it helps you!

it has to be b, about 97 percent.