Lesson 03 - Practice Problems

1. Solve the table for the empty cells based on the image below.

Variable	Circuit #1	Circuit #2	Circuit #3	Circuit #4
R1	500Ω		2KΩ	100 Ω
I1	40mA	600 mA
V1		8V	12V
P1				4W

2. For the circuit below, solve the table for the empty cells.

   

Variable	Circuit #1	Circuit #2	Circuit #3	Circuit #4
R1	50 kΩ		2MΩ	400Ω
I1	100mA	15mA
V1		800 mV	1kV
P1				9W

3. Which flashlight design is better if your main concern is power consumption?

   

Option 1	Option 2
R1 = 90 Ω	R1 = 50 Ω
V1 = 9V	V1 = 6V
P1 =	P2 =

4. Two light bulbs, one rated at 50 W and the other rated at 100 W bulb are each connected to a 110 V source. Which bulb draws more current?

5. The lighting for a new UAS control console is modeled as a voltage source and a resistor, as shown below. For each of the following proposed options, find the unknown value. If the sole measure of merit is to minimize current, which of the six options is best?

   

Variable	Circuit #1	Circuit #2	Circuit #3	Circuit #4	Circuit #5	Circuit #6
R1	5.4 kΩ	4.8 kΩ	7.4 KΩ	100 Ω
I1	2 mA	5 mA
V1			8V

6. The GPS receiver for an experimental cruise missile can be modeled as a single resistor connected to a voltage source. Given the six designs below, if the sole measure of merit is to minimize power consumption, which of the designs is best?

   

Variable	Circuit #1	Circuit #2	Circuit #3	Circuit #4	Circuit #5	Circuit #6
R1			8.2 KΩ	4.8 kΩ	1.5 kΩ	1.2 kΩ
I1	15 mA	8 mA		5 mA	12 mA
V1	1.5 V	2.4 V			9V	12V
P1

7. Given the following model of the cooling system of a laptop computer, clearly articulate how the current in the circuit would change if the resistance of the fan doubled from 1.5 kΩ to 3.0 kΩ .

   

8. Given the following model of an electric clock, clearly articulate how the power consumed by the clock would change if the voltage source decreased from 9.0 V to 4.5 V.

   

9. To be effective as an illumination source, the thunderstorm lighting of an aircraft modeled as a single 10 Ω resistor connected to a voltage source must consume a minimum of 250 W.

(a) Would a 28-Volt battery be an acceptable voltage source?

(b) What is the minimum allowable voltage for the voltage source?

10. A background light for a home stereo system is limited to 1 W to prevent damage to the stereo housing. The light is modeled as a single 100 Ω resistor.

(a) Is a current of 9.2 mA acceptable?

(b) What is the maximum allowable current in the circuit?