Q1: Draw
a simplified circuit with only series circuit elements.
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Q2: Draw
a simplified circuit with only ONE series resistor
-
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Q3:
Find the total equivalent resistance for all resistors in this
circuit.
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- Total resistance is 56.7W R2
and R3 are parallel and must be added first. Let R23 equalLet
R23 equal R2 and R3 added together
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1/R23 = 1/R2 + 1/R3
1/R23 = 1/20.0 W +
1/10.0 W
1/R23 = 3/20 W
1/R23 = .15 1/W
R23 = 6.7 W
Replacing R23 for R2 and R3
we can now add all resistors in series.
R1 + R23 + R4 + R5
= Total Resistance
20.0 W + 6.7 W
+ 20.0 W + 10.0 W
= 56.7 W
Total Resistance = 56.7 W
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- .
- Q4:
What current flows through the battery?
Total current through the battery is 0.18 A. [1 pt]
- .
- V = IR
- .
- 10 V = I (56.7 W)
- .
- I = 10 V/56.7 W
- .
- I = 0.176 A
Q5:
What current flows through each resistor?
R1, R23, R4, and R5,
all have 0.18 A of current.
-
For R1, R4, and R5
I(R1) = I(T) = 0.176 A
R2 and R3 must be found individually using
the Voltage drop across R23:
-
-
V23 = I23 * R23
V23 = 0.176 A (6.7 W)
V23 = 1.18 V
This voltage drop is the same for R2 and R3,
therefore:
-
V23 = I2 * R2
1.18 V = I2 * 20.0W
I2 = 0.059 A
V23 = I3 * R3
1.18V = I3 * 10.0W
I3 = 0.118 A
- Q6:
What is the potential difference (voltage drop) across
each resistor?
Voltage drop for each resistor must equal total voltage drop
for entire system, which is 10.0 V.
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-
-
-
-
For R1, and R4
V = IR
V = 0.176 A * 20.0W
V = 3.52 V
For R5, V = IR
V = 0.176 A * 10.0
W
V = 1.76 V
For R23, V = IR
V = 0.176 A * 6.7W
V = 1.18 V
Because R2 and R3 are in parallel you must
use their combined resistance to find the voltage drop over each
individual resistor.
-
- For R2, V = IR V = 0.059 V
-
- A * 6.7W = 0.40 V
For R3, V = IR
V = 0.118 A * 6.7 W
V = 0.80 V
- All voltages add up to the total voltage drop across the
battery.
-
-
3.52 V + 3.52 V + 1.76V + 0.40 V + 0.80 V = 10.0 V
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