Transcript What is Resistance?

Welcome!
The Topic For Today Is…
Your Topic
Tools we use to Resistance and
measure
Resistivity
Current
Electricity
Series and
Parallel Circuits
Cut out the
Static
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Bonus Question: 5000 pts
Topic 1: 200
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Question:
Ammeters measure…
Answer
Current
Topic 1: 400
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Question:
Voltmeters measure…
Answer
Potential Difference
Topic 1: 600
• Question:
• Ammeters are connected in
while voltmeters are connected in
• Answer
• Series; Parallel
.
Topic 1: 800
• Question:
• Ammeters have
while voltmeters have
resistance.
• Answer
• Very little; Very much
resistance
Topic 1: 1000
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Question:
A galvanometer is…
Answer
A device to measure extremely small
currents.
Topic 2: 200
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Question:
What is resistivity?
Answer
Resistivity is an intrinsic property of a
material, which is a measure of the
conductive ability of the material. The lower
the value, the more conductive the material
is.
Topic 2: 400
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Question:
What is a resistor?
Answer
A component in an electrical circuit, which
“resists” the flow of electrons.
Topic 2: 600
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Question:
What is Resistance?
Answer
The ratio of the voltage drop across a device
to the current flowing in it.
V
R
I
Or the hindrance to the flow of charge.
Topic 2: 800
• Question:
• As the length of a conductor increases, its
resistance will
while its resistivity
will
.
• Answer
• Increase; remain the same
Topic 2: 1000
• Question:
• Determine the resistance of a copper wire
that is 2.00 meters in length and has a radius
of 150.m
• Answer
• 0.487
Topic 3: 200
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Question:
Conventional Current is…
Answer
the flow of positive charge.
Topic 3: 400
• Question:
• A 40 Volt battery is connected to a 20 Ohm
resistor. What is the current flowing in the
circuit?
• Answer
• 2 Amperes
Topic 3: 600
• Question:
• 2 amperes of current is equivalent to how
many electrons per second?
• Answer
• 1.25x1019 electrons per second
Topic 3: 800
• Question:
• A cloud transfers 25 Coulombs of charge to
the earth during a discharge lasting 0.75
seconds. What is the current flow.
• Answer
• 33.3 Amperes
Topic 3: 1000
• Question:
• A cloud transfers 10,000 Coulombs of charge
to the earth during a discharge lasting 0.50
seconds. If the potential difference between
the cloud and the ground is 25,000,000 Volts,
what is the resistance of the atmosphere?
• Answer
• 1250 Ohms
Topic 4: 200
• Question:
• How do you find the total resistance and
voltage in a series circuit?
• Answer
• You sum up the individual values for R and V.
Topic 4: 400
• Question:
• Adding another resistor to a series circuit will
cause the equivalent resistance to…
• Answer
• Increase
Topic 4: 600
• Question:
• A 2, 4 and 6 Ohm resistor are connected in
parallel. Which resistor will have the greatest
current and which one will have the least?
• Answer
• The 2 resistor will have the greatest current
while the 6 resistor will have the least.
Remember: Electricity follows the path of
least resistance.
Topic 4: 800
• Question:
• Determine the equivalent resistance for 3
identical 6 resistors connected in series and
parallel
• Answer
• In series: Req = 18
• In parallel: Req = 2
Topic 4: 1000
• Question:
• A 16 and 26 Ohm resistor are connected in
parallel across a potential difference of 40. V.
What is the current in the circuit?
• Answer
• 4.0A
Topic 5: 200
• Question:
• Electric field lines go from
.
• Answer
• Positive to negative
to
Topic 5: 400
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Question:
The units for the electric field intensity are:
Answer
N/C or V/m
Topic 5: 600
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Question:
Conservation of charge means…
Answer
The total charge of a system is constant. It
can neither be created, nor destroyed.
Topic 5: 800
• Question:
• Explain why a neutral object can be attracted
to a charged object.
• Answer
• Due to separation of charge. Electrons are
either attracted to the surface or repelled
resulting in a surface charge.
Topic 5: 1000
• Question:
• A proton experiences a force of 2.0x10-20N.
What is the electric field?
• Answer
• 0.125N/C
Bonus Question:
5000 pts.
• Question:
• A proton is released from rest between two
parallel plates where the electric field
strength is 25,000 V/m. Determine the
acceleration of the proton.
• Answer
• 2.4x1012 m/s2
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Daily Double
The Winner Of The Last Round
Write Down How Much Money
You Are Willing To Risk
If You get the Question write you win that money
If you get it wrong you Loss the money!