Download Electricity Unit Assignment

6/27/2017
P30 Unit B UA pt. A –
Electricity
Name: ______
Date: ______
Show all work, including starting equations, units and proper sig-digs, to receive full
marks.
1. In a classroom demo, the dome of a Van de Graaff generator was initially charged
negatively. A stream of closely spaced neutral soap bubbles was blown toward the dome
of the generator. Much to the surprise of the LD and his students, the following
observations were made:
1. The bubbles were initially attracted to the dome
until the first bubble hit the dome.
2. The first bubble hit the dome and splattered
3. All the other bubbles stopped in mid-air before
repelling from the dome of the generator and from
each other.
Using the concepts of electrostatic forces and charge distribution, explain:
 Why the soap bubbles were initially attracted to the top of the generator. (2
marks)
 Why, after the first bubble splattered, the other bubbles were repelled away from
one another. (2 marks)
A diagram or diagrams may be used to help you communicate your idea.
2. A single neutral 2.00 g pithball is touched by a charged
rubber rod which had a charge of 2.3 x 10-8 C. The pithball then
comes into contact with another pithball of equal size and
shape. If the two pithballs are hung by two pieces of 3.00 cm
thread from a single point (as shown) forming an angle of 15.0˚,
what is the charge remaining on the original charged rod?
(1.46 x 10-8 C) (4 marks)
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6/27/2017
Use the diagram to the righ to answer the next
question:
3. A proton, electron and alpha particle are arranged as
shown above. Using your data table and the diagram
given, determine the magnitude and direction of the
electric force acting on the proton due to the alpha
particle and the electron.
(5.9 x 10-18 N 74° S of W) (6 marks)
4. Draw a diagram showing the field lines in each of the following situations. (Cut and
paste the diagrams at the end of this package into your unit assignment!) (1 mark for
each diagram)
Use the diagram to the right to answer the next question.
5. In the early 1800’s LD’s favorite scientist from
history, Michael Faraday performed an experiment used
to investigate electric fields. This is now called
Faraday’s Ice Pail Experiment.
In the experiment, a hollow conducting ice pail is
placed on an insulated plate. One electroscope is
attached to the outside of the pail and one is attached to
the inside of the pail.
A positively charged rod is brought into the pail. Predict which electroscope will show a
deflection when the rod is brought into the pail and justify your response using the
principles learned in class (HINT: page 557-558 of your Pearson) (3 marks)
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6/27/2017
6. A negative charged particle that has a mass of 2.8 x 10-16 kg accelerates upwards at 2.8
m/s2 in the electric field between two horizontal plates that have a separation of 0.15 m.
The potential difference across the plates is 4.2 x 102 V. Taking into consideration the
force of gravity, find
a) The magnitude and direction of the electric force on the particle.
(3.5 x 10-15 N up) (3 marks)
b) The magnitude of the particle’s charge.
(1.3 x 10-18 C) (3 marks)
7. An electron, travelling horizontally at a speed of 5.45 x 106 m/s, enters a parallel plate
capacitor with an electric field of 125 N/C between the plates. The separation between
the plates is 6.20 mm. Ignoring gravitational effects, if the electron passes from the top
plate to the bottom plate, how far will it have traveled into the capacitor? (0.130 m) (3
marks)
Cut and paste these diagrams!
Bonus Questions: Answer Only ONE!!!
Fair Bonus Question: Describe Michael Faraday’s youth.
Unfair Bonus Question: Who has the best afro? Justify your response.
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