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NASA-Threads
Electricity & Magnetism
Lesson 17: Ohm’s Law
Homework
1. A student found that the current through a 100Ω resistor was 0.1 A. What would be
the voltage across the resistor?
2. A student measured a current of 25mA through a 220Ω resistor. What would be the
voltage across the resistor?
3. An engineer set up a circuit with a 6V battery source. If she puts a 150Ω resistor in
series with the batteries, what current should she measure? Express your answer in
both amps and milli-amps.
4. A physicist set up a circuit with a single AA battery. If he puts a 10kΩ resistor in
series with the battery, what current should he measure?
5. A student connected a 3V battery source to a resistor. If she measures a current of
10mA, what would be the value of resistance?
6. An engineer connected a 4.5V battery source to a resistor and measured a current of
0.05A. The engineer then decided to replace battery pack with a 6V source. If the
engineer wants to maintain a current of 0.5A, what would be (a) the original value of
resistance, and (b) the value of the new resistor?
NASA-Threads
Electricity & Magnetism
Lesson 17: Ohm’s Law
Homework Solution
1. A student found that the current through a 100Ω resistor was 0.1 A. What would be the voltage
across the resistor?
V  IR
V  0.1A 1000
V  100V
2. A student measured a current of 25mA through a 220Ω resistor. What would be the voltage
across the resistor?
V  IR
V  25mA 
1A
 220
1000mA
V  5.5V
3. An engineer set up a circuit with a 6V battery source. If she puts a 150Ω resistor in series with
the batteries, what current should she measure?
V
R
6V
I
150
I  .04 A
I
I  .04 A 
1000mA
1A
I  40mA
4. A physicist set up a circuit with a single AA battery. If he puts a 10kΩ resistor in series with the
battery, what current should he measure?
V  1.5V
V
R
1.5V
1k 
I

10k  1000
I  .00015 A
I
NASA-Threads
Electricity & Magnetism
Lesson 17: Ohm’s Law
5. A student connected a 3V battery source to a resistor. If she measures a current of 10mA, what
would be the value of resistance?
V
I
3V
1000mA
R

10mA
1A
R  300
R
6. An engineer connected a 4.5V battery source to a resistor and measured a current of 0.05A. The
engineer then decided to replace battery pack with a 6V source. If the engineer wants to
maintain a current of 0.5A, what would be (a) the original value of resistance, and (b) the value
of the new resistor?
V
I
4.5V
R1 
.05 A
R1  90
R
6V
.05 A
R2  120
R2 