Question

12. A charged balloon is placed near the wall. This attracts the protons in the wall while
repelling the walls electrons. This is an example of ...
a. conduction b. conductor c. induction d. Friction
13. A person walks across the carpet, rubbing their feet. Next, they touch the doorknob,
transferring electrons into the doorknob. Which statement demonstrates conduction?
a. Walking across the carpet
b. Touching the doorknob
c. No conduction was demonstrated.
14. An electrically charged metal rod touches a neutral metal ball. Which statement best
describes what will happen next.
a. The protons within the rod will be transferred into the metal ball and spread out evenly across
the metal ball.
b. The electrons within the rod will be transferred into the metal ball and stay in a central
location.
c. The protons within the rod will be transferred into the metal ball and stay in the central
location.
d. The electrons within the rod will be transferred into the metal ball and spread out evenly.
15. Magnets can be temporary or permanent. Give an example of each one.
Permanent magnet:
Temporary magnet:
Section 4: Introduction to Waves.
16. A student was listing the electromagnetic wave from the weakest to the strongest. What
mistake did she make?

Answer 1

12. c. induction — the charged balloon causes charge separation in the wall without contact (electrostatic induction).

13. b. touching the doorknob — conduction is transfer of charge by direct contact.

14. d. The electrons within the rod will be transferred into the metal ball and spread out evenly — in conductors only electrons move and they redistribute over the connected conductors.

15. Permanent magnet: a bar magnet or refrigerator magnet.
Temporary magnet: an iron nail or paperclip that becomes magnetized near a magnet, or an electromagnet (magnetic only while current flows).

16. Most likely mistake: confusing “weakest/strongest” (energy/frequency) with wavelength or reversing the order. The correct order from weakest (lowest energy/frequency, longest wavelength) to strongest (highest energy/frequency, shortest wavelength) is: radio → microwave → infrared → visible → ultraviolet → X-rays → gamma rays.