Name:    Test Your Knowledge:  Nuclear Decay Mathematics

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.

1.

A vial contains 100mCi of an unidentified radionuclide at 10am Thursday. At 10am Friday, the activity has decayed to 25 mCi. What is the half-life of the unidentified radionuclide?
 a. 12 hours c. 24 hours b. 100 hours d. 4 hours

2.

If an assay of a vial containing Molybdenum shows 50 mCi present on June 1st, approximately what will the assay show on June 24th?  DF=  .1256
 a. 7.88 mCi c. 6.28 uCi b. 6.28 mCi d. 398 mCi

3.

At some point in time a source has an activity of 1,000 mCi. At a later point in time the activity is 62.5 mCi. The half-life is unknown. How many half-lives have elapsed?
 a. four c. three b. can’t be determined from data provided d. five

4.

Convert 4.1 MBq to mCi:
 a. 11 mCi c. .11 mCi b. 151.7 mCi d. 41.1 mCi

5.

Convert 15 mCi to MBq:
 a. .4 MBq c. 52 MBq b. 555 MBq d. 5550 MBq

6.

Convert 119 Rems to Sieverts:
 a. .119 Sv c. 1.19 Sv b. 11.9 Sv d. 119 Sv

7.

The Half Value Layer for I-123 in lead is .3 mm.  A dose generates 5300 mR/hr.  What will the exposure be for the technologist if a .90 mm slab of lead is placed inbetween the source and the technologist?
 a. 530 mR/hr c. 662.5 mR/hr b. 662.5 mCi/hr d. 526 mR/hr

8.

Convert 31 MBq to mCi:
 a. 68 mCi c. .837 mCi b. 1147 mCi d. 1.19 mCi

9.

A vial of Technetium eluate contains 50 mCi/ml.  If 4 mls are withdrawn and added to a MDP Kit containing 16 mls of normal saline, what volume would then be needed to be withdrawn to prepare a 20 mCi unit dose at that moment?
 a. 4 ml c. .2 ml b. 2.5 ml d. 2 ml

10.

Convert 38 mRem to mSv:
 a. 3.8 mSv c. .038 mSv b. .38 mSv d. 38 mSv

11.

 a. 80 Grays c. .08 Grays b. .8 Grays d. 8 Grays

12.

Convert 25 mCi to MBq:
 a. 925 MBq c. 62 MBq b. 92.5 MBq d. 925 Bq

13.

One-hundred twenty-seven millicuries is equivalent to how many megabecquerels?
 a. 4,699 MBq c. 4.70 MBq b. 46.99 MBq d. 3.4 MBq

14.

A reagent kit contains approximately 140 mCi of Tc99m Sulfur Colloid in 23 mls at 9am.  How much volume must be withdrawn to obtain a dose of 5 mCi at 3 pm?
 a. 1.7 ml c. 2.0 ml b. 1.64 ml d. 1.6 ml

15.

100 uCi =______mCi:
 a. 100 c. 0.1 b. 0.01 d. 1000

16.

If the exposure rate at 10 meters from a cobalt sheet source is 15 mR/hr, what will the exposure rate be at 25 meters?
 a. 3 mR/hr c. 6 mR/hr b. 10 mR/hr d. 2.4 mR/hr

17.

If the exposure rate at 4 meters from a radioactive source is 5 mR/hr, what will the exposure rate be at 3 meters?
 a. 6.5 mR/hr c. 2.8 mR/hr b. 8.9 mR/hr d. 7.4 mR/hr

18.

Convert 9.25 MBq to mCi:
 a. 342.2 mCi c. .25 mCi b. 25 mCi d. 46.25 mCi

19.

Convert 4 Rems to Sieverts:
 a. 4 Sv c. .04 Sv b. .4 Sv d. 40 Sv

20.