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Conceptual Physics Labs – Chapter 14
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Name _______________________________
Where appropriate – ALWAYS show your formulas and your work!
Use the back of your paper if you need to.
Charging by Friction Suspend two balloons from the ceiling as
shown Rub each of the balloons on someone’s hair, then let the
balloons suspend freely. Sketch the reaction below and tell what
happened and WHY it happened. Polarization Rub a balloon on your
hair and stick it to the wall. Sketch and label a detailed
explanation of the electric charges and reactions.
Charge a friction rod and bring it near a small, steady stream
of water. Sketch and label a detailed explanation of what
happened.
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Conceptual Physics Labs – Chapter 14
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Charging by Induction Using the electroscope, charge a balloon
or friction rod and bring it close to (but NOT touching) the coiled
wire of the electroscope. Observe what happens with the aluminum
leaves. Sketch the reaction below and tell what happened and WHY it
happened. Touch and hold the coiled wire to discharge the
electroscope. Now, charge the balloon again and bring it near the
coiled wire again. This time, touch ONE finger to the coiled wire
and watch what happens. Move your finger and the balloon away –
what happens with the aluminum leaves. WHY? Make sure you have
discussed positive and negative charges in all of your explanations
thus far in the lab.
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Conceptual Physics Labs – Chapter 14
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Coulomb’s Law Calculate the force between a 0.006C charge and a
0.001C charge 4 meters apart. Show ALL your work. The force between
a pair of charges is 100 newtons. The distance between the charges
is 0.01 meter. If one of the charges is 2 x 10-10 C, what is the
strength of the other charge? Show ALL your work.
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Conceptual Physics Labs – Chapter 14
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Capacitors Wire your Electronics board using the following
diagram – notice that one wire is to remain loose. Hold the loose
wire to the spring at #27 and then remove it. Then, touch the loose
wire to the base of spring #43 – watch the LED (remember, they
aren’t very
bright, so watch it closely)
1) What happened with the LED bulb? 2) Explain WHY this happened
– be detailed.
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Conceptual Physics Labs – Chapter 14
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Thinking Ahead Using the Van de Graaff generator (and carefully
following the instructions you are given), create a 2” spark from
the device to the wand. Tell me, in detail, what happened. Note –
we won’t really discuss this fully for several chapters, but you
know enough to figure this out. And.. back to Coulomb’s Law
Consider the electric force between a pair of charged particles a
certain distance apart. By Coulomb’s Law: 1) If the charge on one
of the particles is doubled, the force is (Circle the correct
answer)
(unchanged) (halved) (doubled) (quadrupled)
2) If, instead, the charge on both particles is doubled, the
force is
(unchanged) (halved) (doubled) (quadrupled)
3) If, instead, the distance between the particles is halved,
the force is
(unchanged) (halved) (doubled) (quadrupled)
4) If the distance is halved AND the charge of both particles is
doubled, the force is _______________ time as great.
