All AP Physics 1 Resources
Example Questions
Example Question #175 : Electricity
If a lightbulb has a resistance of , how much current is going across the lightbulb?
The power in a circuit is determined by the equation , where is the power of the circuit, is the current in the circuit, and is the equivalent resistance of the circuit.
Solving the power equation for current gives
In this problem,
Example Question #251 : Electricity And Waves
How much energy does a lightbulb give off in ?
Not enough information
Energy is related to power by the equation , where is energy, is the power of the circuit, and is time.
Time needs to be in seconds.
For our problem, energy is
Example Question #252 : Electricity And Waves
What is the circuit power of a circuit with a battery with potential difference , and 3 resistors in parallel with equivalent resistances of ?
Recall the formula for circuit power:
We know that . To determine resistance of 3 resistors in parallel we set up the equation for total resistance for resistors in parallel:
From our formula we know that the circuit power is:
Example Question #183 : Electricity
Consider a series circuit with a battery. The circuit is composed of three resistors, . Calculate the power (units of Watts ) of the circuit.
We can write the power of a circuit as:
This however, does not help much because we do not know the current in the circuit. But by Ohm's law:
Substitution of this expression into the expression for power gives us:
Where , the total resistance of the circuit. For a circuit in series, the total resistance is simply the sum of the resistors:
Therefore, the power of the circuit is:
Example Question #184 : Electricity
Calculate the power of a circuit composed of a battery and three resistors in parallel. The resistors have resistance values of
The power of a circuit is given by:
.
By substitution of Ohm's law, we can show that:
Where , or the total resistance of the circuit. For resistors in parallel, we add the inverses of their values. This is shown more plainly as:
From the given values, we can calculate the total resistance as . This leads us to the final answer:
Example Question #141 : Circuits
You are given the following circuit powered by a battery:
Find the power supplied by the battery.
The power provided by the battery is equal to the product of the current that passes through it and the voltage it provides. In order to find the current, you must find the equivalent resistance of the circuit.
Since R1 is in series with R2 and R3, who are in parallel, the equivalent resistance is given by:
Then, to find power, you can use the following formula:
The battery supplies of power.
Example Question #254 : Electricity And Waves
How much power does a circuit produce if there is an equivalent resistance of and a current of ?
The equation for power in a circuit is given as:
is the power in Watts, is the current in amps, and is the resistance in ohms. By solving the equation and substituting our values, we obtain:
Example Question #187 : Electricity
A capacitor with a capacitance of stores of energy. What is the voltage across this capacitor?
The correct answer is .
We can obtain this answer with the following equation regarding capacitors:
is the energy stored on the capacitor, is the capacitance, and is the voltage.
Solving for we obtain:
Example Question #255 : Electricity And Waves
What is the power of a circuit with a resistance of and current?
We calculate the power in a circuit using the following equation
Given and
Example Question #189 : Electricity
What is the power of a circuit with a resistance of and current?
We calculate the power in a circuit using the following equation
Given and