Unit 8 Extra
Either print this page and complete or
(better yet) neatly show your answers on a separate page of paper.
All answers must be expressed as complete sentences and/or all work
shown to receive credit.
- Distinguish between a positively and negatively charged object
in terms of the number of protons and electrons present in the
- When combing your hair, electrons are scuffed from your hair
onto the comb. Is your hair then positively or negatively charged?
How about the comb?
- What is the fundamental force that underlies all "chemical"
- Explain how electrically neutral atoms and molecules are able
to electrically attract each other.
- How are electrical forces (as described by Coulomb's law)
similar to gravitational forces (as described by Newton's law of
gravitation)? How are they different?
- Distinguish between a conductor and an insulator; between a
conductor and a semiconductor.
- EIn the "good ole days" (when Mr. Schmidgall was a youngster)
at automobile toll-collecting stations, a thin metal wire would
stick up from the road and make contact with cars before they
reached the toll collector. What was the purpose of this wire?
- Why are the tires for trucks carrying gasoline and other
flammable fluids manufactured to conduct electricity?
- If you rub an inflated balloon against your hair and place it
against a door, it will stick. Explain why.
- Explain how an electrically neutral object can be attracted to
a charged object.
- A spark will jump between you and another person if the
electric field exceeds 4.0 x 106 V/m. You shuffle across a rug and
a spark jumps when you stick out your finger 0.15 cm from another
person's arm. Calculate the potential difference between your body
and the other person's arm. PSYW
- An oil drop carries a charge of three electrons and is
suspended in an electric field of intensity 5.0 x 104 N/C. If the
charge on the electron is 1.6 x 10-19 C, what is the weight of the
oil drop? PSYW
- An electric force of 2.5 x 10-4 N acts between two small
equally charged spheres which are 2.0 cm apart. Calculate the
force acting between the spheres if the charge on one sphere
doubles and the spheres move to a 5.0 cm separation.
- A charge of 4.0 x 10-5 C is attracted to a second charge with
a 350 N force when the separation is 10.0 cm. Calculate the
magnitude of the second charge. PSYW
Resources for physics students are available through
links on the
Physics Home Page. Such resources include the
Physics Studios (a collection of animations and movies which
illustrate key physics concepts) and
Physics Classroom (an online tutorial written in an
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