A fixed radiation source delivers 2 mSv/h. How long would it take to reach 10 mSv?

A fixed radiation source delivers 2 mSv/h. How long would it take to reach 10 mSv?

• A. 2.5 hours
• B. 10 hours
• C. 20 hours
• D. 5 hours

Answer: (D)

Dose adds up at a constant rate, so the total dose equals the dose rate multiplied by the time of exposure. If the rate is 2 mSv per hour, every hour adds 2 mSv. To reach a total of 10 mSv, you need 10 ÷ 2, which is 5 hours. This checks out because 2 mSv/h × 5 h = 10 mSv. If you spent less time, you’d accumulate less than 10 mSv; if you spent more time, you’d exceed 10 mSv.

Dose adds up at a constant rate, so the total dose equals the dose rate multiplied by the time of exposure. If the rate is 2 mSv per hour, every hour adds 2 mSv. To reach a total of 10 mSv, you need 10 ÷ 2, which is 5 hours. This checks out because 2 mSv/h × 5 h = 10 mSv. If you spent less time, you’d accumulate less than 10 mSv; if you spent more time, you’d exceed 10 mSv.