Page 40 - Teach Yourself Electricity and Electronics

20 Basic physical concepts

4. An ion:
A. Is electrically neutral.
B. Has positive electric charge.
C. Has negative electric charge.
D. Might have either a positive or negative charge.

5. An isotope:
A. Is electrically neutral.
B. Has positive electric charge.
C. Has negative electric charge.
D. Might have either a positive or negative charge.
6. A molecule:
A. Might consist of just a single atom of an element.
B. Must always contain two or more elements.
C. Always has two or more atoms.
D. Is always electrically charged.
7. In a compound:
A. There can be just a single atom of an element.
B. There must always be two or more elements.
C. The atoms are mixed in with each other but not joined.
D. There is always a shortage of electrons.
8. An electrical insulator can be made a conductor:
A. By heating.
B. By cooling.
C. By ionizing.
D. By oxidizing.
9. Of the following substances, the worst conductor is:
A. Air.
B. Copper.
C. Iron.
D. Salt water.

10. Of the following substances, the best conductor is:
A. Air.
B. Copper.
C. Iron.
D. Salt water.