20
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Regents Physics
Worksheet 4.2.3 – Ohm’s Law and Electrical Power (20 points)
Show all work – multiple choice answers MUST be proven for full credit!
1.
A 1.5 volt battery is connected to a 10 ohm resistor.
a.
Match the set of variables for questions 3 through 7 to one of the
five graphs below.
What current passes through the resistor?
A
D
E
Relationship between voltage and current for a fixed
resistance.
4.
Relationship between power and current for a fixed
voltage.
5.
Relationship between power and resistance for a fixed
voltage.
6.
Relationship between power and current for a fixed
resistance.
7.
How much current passes through a 12 ohm circuit
operating at 3.0 volts?
What is the power developed by this resistor?
[0.225 W]
2.
C
3.
[0.15 A]
b.
B
A 100 watt light bulb draws 820 milli-amperes of current.
a.
Determine the voltage that is being applied to
the light bulb.
[122 V]
b.
Calculate the energy usage of this light bulb over
the course of 2.0 hours.
(1) 0.25 A
(2) 0.75 A
Proof: Show calculations.
[7.2 x 105 J]
(3) 3.0 A
(4) 4.0 A
8.
The ratio of the potential difference across a conductor to
the current in the conductor is called
(1) conductivity
(2) resistance
(3) charge
(4) power
Proof: Demonstrate using an equation.
9.
The resistance of a 60 watt light bulb operated at 120 volts
is approximately
(1) 720 Ω
(2) 240 Ω
(3) 120 Ω
(4) 60 Ω
Proof: Show calculations.
10. A toaster connected to a 120 volt circuit draws a current of
6.0 amperes. How much electrical energy does the toaster
use in 5.0 seconds?
2
(1) 1.4 x 10 J
2
(2) 7.2 x 10 J
Proof: Show calculations.
4
(3) 2.2 x 10 J
3
(4) 3.6 x 10 J