1.
The circuit in the drawing contains three identical resistors in a series circuit . The
20 V battery delivers 60 W of power to the circuit. (a)What is the total current in the
circuit ? Show the direction and amount of current in the circuit. (b)What is the
resistance of each resistor ? (c) What is the voltage across the first resistance. Show
how you would introduce an ammeter and voltmeter in the circuit below. (15 pts)
R
R
R
20 V
Total resistance = 3 R
Total current I = 60 W / 20 V = 3 A (flows counter clockwise)
3 R = total voltage / total current = 20 V / 3 A
So R = 20 /9 = 2.22 

When showing in the circuit diagram insert four voltmeters across power supply and each
of the three resistances. Also show ammeter in series.
The following shows a parallel circuit with three resistors (R1 = 36 , R2 = 24 , R3 = 8
, connected to a 20 V battery. (a) What are i1 i2 and i3. What is the total current
provided by the battery? Show the currents and their direction in the circuit below. (b)
What is the equivalent resistance of the circuit? (c) What are the voltages across the
three resistances equal to? (15 pts)
20 V
Current in first branch I1 = 20 V / 36 
Current in first branch I2 = 20 V / 24 
Current in first branch I1 = 20 V / 8 
Total current I = 3.89 A
All currents are counter clockwise
Total resistance R = total voltage/total current = 20 V / 3.893 A = 5.143 

For full credit, draw the circuit diagrams neatly labeling all the elements (voltages
and resistances) and showing the directions of current flow in the circuit at the
appropriate places.
2. (a) Build a series circuit, with a 200 , 350  and 650  resistances connected to a
12 V battery. What is the total resistance and current in the circuit, and what are the
voltages across the three resistances? What is the sum of the voltage drops across the
resistors equal to? (15 points)
You need to draw the circuit similar to what you did in the Lab
The total resistance of the circuit R = 1200 
The current in the circuit I = 12 V / 1200 0.01 A
V1 = I R1 = 2 V
V2 = I R2 = 3.5 V
V3 = I R3 = 6.5 V
V1 + V2 + V3 = V = 12 V (verified)
(b) Build a parallel circuit with 16 , 24  and 40  resistors connected to a 24 V
battery. What are the currents in the three branches and what are the voltages across the
resistors each equal to. What is the total current from the battery equal to? What is the
total resistance? (15 points)
You need to draw the circuit similar to what you did in the Lab
The voltage across the circuit V = 24 V
I1 = V / R1 = 1.5 A
I2 = V / R2 = 1 A
I3 = V / R3 = 0.6 A
I1 + I2 + I3 = I = ? 3.1 A
The total resistance of the circuit R = total voltage / total current = 24 V / 3.1 A =
7.742 
Verify if this R is equal to the equivalent resistance in a parallel circuit.
1 / R = 1 / 16 1 / 24 1 / 40 

R = 0.1292 / 

R = 7.742 verified)