EXERCISES, LESSON 1

REQUIREMENT. The following exercises are to be answered by marking the lettered response that best answers the question, or by completing the incomplete statement, or by writing the answer in the space provided at the end of the question. After you have completed all the exercises, turn to "SOLUTIONS TO EXERCISES" at the end of the lesson and check your answers.

1. A (an) ______________ is a substance which cannot be separated into simpler substances by ordinary chemical means.

     a. Compound.

     b. Atom.

     c. Molecule.

     d. Element.


2. It is the number of __________________ in the nucleus of an atom that determines the element to which the atom belongs.

     a. Protons.

     b. Electrons.

     c. Neutrons.

     d. Mesons.


3. Two atoms of the same element with different numbers of neutrons are called_________________________.

     a. Isotones.

     b. Isobars.

     c. Isotopes.

     d. Isomers.


4. In the atomic notation zX, the letter A represents:

     a. The number of electrons in the atom.

     b. The number of neutrons in the atom.

     c. The number of protons in the atom.

     d. The number of protons plus neutrons in the atom.


5. Naturally-occurring radioactive materials produce_________________ and ___________________radiations.

     a. Alpha, beta, neutron.

     b. Alpha, beta, gamma.

     c. Proton, alpha, gamma.

     d. Beta, gamma, neutron.


6. The radiation with the greatest penetrating ability is:

     a. Beta.

     b. Alpha.

     c. Neutrons.

     d. Gamma rays.


7. In beta decay, the atomic mass number:

     a. Increases by one.

     b. Stays the same.

     c. Decreases by one.

     d. Decreases by four.


8. A radioactive material which decays through five half-lives will result in __________ of the original amount.

      a. 1/8.

      b. 1/16.

      c. 1/32.

      d. 1/61.


9. The roentgen is a unit of x or gamma radiation:

      a. Exposure.

      b. Absorbed dose.

      c. Accumulative dose.

      d. Energy absorption.


10. The rad represents an absorption of:

     a. 93 ergs/gram.

     b. 93 calories/gram.

     c. 100 ergs/gram.

     d. 100 calories/gram.


11. When radiation is absorbed by a living cell, the primary damage is by:

     a. Formation of cell poisons.

     b. Genetic rearrangement within the cell nucleus.

     c. Loss of cell protoplasm and nuclear material.

     d. Ionization and excitation of the atoms and molecules of that cell.


12. The LD-50 for radiation exposure in man is:

     a. 100 to 200 rads.

     b. 200 to 500 rads.

     c. 500 to 800 rads.

     d. 800 to 3,000 rads.


13. The length of time it takes for one-half of a given number of atoms of one element to decay into another element is the atom's:

     a. Half-life.

     b. Atomic number.

     c. Radioactive change.

     d. Radioactive stability.


14. Of the following, the most important factor in selecting a radiation detector is:

     a. Weight and portability of the instrument.

     b. Type of radiation.

          c. Cost of the instrument.

     d. Chemical form of the radiation.


15. What types of radiation does the AN/VDR-2 detect?

     a. Gamma only.

     b. Gamma and alpha.

     c. Gamma and beta.

     d. Gamma, alpha, and beta.


16. Chronic exposure to radiation may result in which of the following?

     a. Cancer.

     b. Decreased lifespan.

     c. Genetic mutations.

     d. All of the above.


17. When considering the relationship between radiation and genetic effects, it is true that radiation:

     a. Creates new recessive mutations

     b. Creates new dominant mutations.

     c. Increases the rate of mutations already present in the population.

     d. Decreases the rate of mutations already present in the population.