determine how much dose a person would receive
Using the following equation: D=4Kr^-2 D=(4K)/r^2 D = 40, r = 7 40 = (4k)/7^2 40*49=4K K = 490 c. Use the value of K you found in the previous question to determine how much dose a person would receive if she were i. 4 feet from the source ii. 12 feet from the source