Final answer:
The approximate entrance skin exposure (ESE) for the average AP supine lumbar spine radiograph is 39.75 milliwatts (mW).
Step-by-step explanation:
The approximate entrance skin exposure (ESE) for the average AP supine lumbar spine radiograph can be calculated using the given information. The ESE is equal to the product of the x-ray beam intensity, the area of the chest exposed, and the fraction of x-rays absorbed in the tissue.
ESE = x-ray beam intensity * area exposed * fraction absorbed
Plugging in the values: ESE = 1.50 W/m² * 0.0750 m² * (0.350) = 0.03975 W = 39.75 mW
The approximate ESE for the average AP supine lumbar spine radiograph is 39.75 milliwatts (mW).