You now have four variables which impact the way a circuit behaves: voltage (V), current (amps), power (W), and resistance (Ω). Given the two main relationships, Ohm's Law and the equation for power, you can come up with quite a few different equations for use in calculations. You also know that current is defined as the number of charges per unit of time.
As long as you are given at least two variables, you can solve for all of them. See if you can use these relationships to answer the questions below.
How many electrons pass by a point every second if a 0.200-amp current is flowing? (e = -1.602 x 10-19 C)
- 3.20 x 10-20 e
- 8.01 x 10-19 e
- 1.25 x 1018 e
- 6.24 x 1018 e
Use the equation \(\mathsf{I = \frac{Q}{\Delta t} }\) first to solve for Q. Then divide by the charge of an electron to find how many electrons are passing.
Use the equation \(\mathsf{I = \frac{Q}{\Delta t} }\) first to solve for Q. Then divide by the charge of an electron to find how many electrons are passing.
Use the equation \(\mathsf{I = \frac{Q}{\Delta t} }\) first to solve for Q. Then divide by the charge of an electron to find how many electrons are passing.
Use the equation \(\mathsf{I = \frac{Q}{\Delta t} }\) first to solve for Q. Then divide by the charge of an electron to find how many electrons are passing.
A 10 Ω wire is connected to a 1.5 V battery. What is the current that flows through the wire?
- 15 amps
- 0.15 amps
- 6.7 amps
- 150 amps
Use Ohm’s law, V = IR, and solve for I.
Use Ohm’s law, V = IR, and solve for I.
Use Ohm’s law, V = IR, and solve for I.
Use Ohm’s law, V = IR, and solve for I.
How much work does a 60-watt bulb do in 1 minute?
- 60 J
- 360 J
- 600 J
- 3600 J
Remember that a watt is Joules per second and there are 60 seconds in a minute.
Remember that a watt is Joules per second and there are 60 seconds in a minute.
Remember that a watt is Joules per second and there are 60 seconds in a minute.
Remember that a watt is Joules per second and there are 60 seconds in a minute.
How much power does a 12-volt circuit use that has a 0.5-amp current flowing through it?
- 2.4 x 101 W
- 2.9 x 102 W
- 6.0 x 100 W
- 4.2 x 10-2 W
Use the equation P = VI to solve for power.
Use the equation P = VI to solve for power.
Use the equation P = VI to solve for power.
Use the equation P = VI to solve for power.
How much power does a 12.0-volt circuit use that has a resistance of 12.0 Ω?
- 1.00 W
- 12.0 W
- 48.0 W
- 144. W
Use the equation \(\mathsf{P = \frac{V^2}{R} }\) to solve for power.
Use the equation \(\mathsf{P = \frac{V^2}{R} }\) to solve for power.
Use the equation \(\mathsf{P = \frac{V^2}{R} }\) to solve for power.
Use the equation \(\mathsf{P = \frac{V^2}{R} }\) to solve for power.
Summary
Questions answered correctly:
Questions answered incorrectly:
