ASNT Industrial Radiography Radiation Safety Practice Test

A radiographer's total exposure for the day after four 10 min exposures in a 100 mR/h field would be:

1. 33.3 mR

2. 66.7 mR

3. 50 mR

4. 100 mR

The correct answer is: 66.7 mR

To determine a radiographer's total exposure for the day, we need to calculate the exposure accumulated from the four separate 10-minute exposures in a field where the radiation level is 100 mR/h. Each exposure has a duration of 10 minutes, which is equivalent to 1/6 of an hour (since there are 60 minutes in an hour). Therefore, for each exposure, the dose received can be calculated as follows: - The exposure rate is 100 mR/h. - The exposure time is 10 minutes, or 1/6 of an hour. To find the exposure for one 10-minute session, you multiply the exposure rate by the time in hours: Total exposure for one exposure = 100 mR/h × (1/6) h = 16.67 mR. Since the radiographer has four exposures of this length, the total exposure for the day can be calculated by multiplying the exposure received in one session by the number of sessions: Total exposure for the day = 16.67 mR/session × 4 sessions = 66.68 mR. Rounding this result gives a total exposure of approximately 66.7 mR. This is why the choice indicating 66.