If 1 count/s equals 1 mSv/h, what is the dose rate for 1,200 counts per minute?

If 1 count/s equals 1 mSv/h, what is the dose rate for 1,200 counts per minute?

• A. 24 mSv/h
• B. 1200 mSv/h
• C. 20 mSv/h
• D. 12 mSv/h

Answer: (C)

The dose rate scales with counts per unit time, so you must align the time units with the given conversion. Convert 1,200 counts per minute to counts per second: 1200 ÷ 60 = 20 counts per second. Since 1 count per second corresponds to 1 mSv/h, 20 counts per second gives 20 mSv/h. Thus the dose rate is 20 mSv/h. (If you used counts per hour instead, you’d divide by 3600 to convert back to per second, and still arrive at the same result.)

The dose rate scales with counts per unit time, so you must align the time units with the given conversion. Convert 1,200 counts per minute to counts per second: 1200 ÷ 60 = 20 counts per second. Since 1 count per second corresponds to 1 mSv/h, 20 counts per second gives 20 mSv/h. Thus the dose rate is 20 mSv/h. (If you used counts per hour instead, you’d divide by 3600 to convert back to per second, and still arrive at the same result.)