Call Now to Set Up Tutoring:

(888) 888-0446

AP Physics 1 : Circuit Power

Study concepts, example questions & explanations for AP Physics 1

Create An Account

All AP Physics 1 Resources

7 Diagnostic Tests 170 Practice Tests Question of the Day Flashcards Learn by Concept

Example Questions

Example Question #21 : Circuit Power

If the voltage of a circuit is doubled, how is the power of a circuit changed? Assume the resistance of the circuit stays the same.

Possible Answers:

Power will stay the same

Power wil be four times larger

Power will double

Power will triple

Correct answer:

Power wil be four times larger

Explanation:

The power in a circuit is determined by the equation $P=I^{2}R$ , where is the power of the circuit, is the current in the circuit, and is the equivalent resistance of the circuit.

To relate power to voltage, we will also need Ohm's law, V=IR , where is the voltage, is the current in the circuit, and is the equivalent resistance of the circuit.

Solving Ohm's law for current gives us $I=\frac{V}{R}$ .

Substituting this form of Ohm's law into the power equation gives us

$P=I^{2}R=\left ( \frac{V}{R} \right )^{2}R=\frac{V^{2}}{R} \right$

$P=\frac{V^{2}}{R} \right$

Assuming the current stays the same, if the voltage is doubled, the power will be four times larger.

Expressed mathematically,

If V=2V

$P=\frac{(2V)^{2}}{R} \right=\frac{4(V)^{2}}{R} \right=4P$

Report an Error

Example Question #174 : Electricity

How much energy does a heat coil produce with it is plugged into a 110V outlet for 5sec and has a resistance of $10\Omega$ ?

Possible Answers:

600J

12500J

35J

6050J

Correct answer:

6050J

Explanation:

The power in a circuit is determined by the equation $P=I^{2}R$ , where is the power of the circuit, is the current in the circuit, and is the equivalent resistance of the circuit.

To relate power to voltage, we will also need Ohm's law, V=IR , where is the voltage, is the current in the circuit, and is the equivalent resistance of the circuit.

Solving Ohm's law for current gives us $I=\frac{V}{R}$ .

Substituting this form of Ohm's law into the power equation gives us

$P=I^{2}R=\left ( \frac{V}{R} \right )^{2}R=\frac{V^{2}}{R} \right$

$P=\frac{V^{2}}{R} \right$

Energy is related to power by the equation $E=P\cdot t$ , where is energy, is the power of the circuit, and is time.

Substituting theequation for power into the equation for energy gives

$E=P\cdot t=\frac{V^{2}}{R} t$

For our problem

$E=P\cdot t=\frac{V^{2}}{R} t=\frac{(110)^{2}}{10} (5)=6050 J$

Report an Error

Example Question #175 : Electricity

If a 60W lightbulb has a resistance of $15\Omega$ , how much current is going across the lightbulb?

Possible Answers:

1Amp

1000Amps

2Amps

10Amps

Correct answer:

2Amps

Explanation:

The power in a circuit is determined by the equation $P=I^{2}R$ , 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

$I=\sqrt{\frac{P}{R}}$

In this problem, $I=\sqrt{\frac{P}{R}}=\sqrt{\frac{60}{15}}=\sqrt{4}=2Amps$

Report an Error

Example Question #251 : Electricity And Waves

How much energy does a 75W lightbulb give off in 5min ?

Possible Answers:

125J

12000J

22500J

Not enough information

Correct answer:

22500J

Explanation:

Energy is related to power by the equation $E=P\cdot t$ , where is energy, is the power of the circuit, and is time.

Time needs to be in seconds.

$5min\times \frac{60sec}{1min}=300 sec$

For our problem, energy is

$E=75\cdot(300)=22500J$

Report an Error

Example Question #252 : Electricity And Waves

What is the circuit power of a circuit with a battery with potential difference 50 V , and 3 resistors in parallel with equivalent resistances of $3 \Omega$ ?

Possible Answers:

278 W

50W

7500W

2500W

Correct answer:

2500W

Explanation:

Recall the formula for circuit power:

$P=\frac{V^2}{R}$

We know that V=50V . To determine resistance of 3 resistors in parallel we set up the equation for total resistance for resistors in parallel:

$\frac{1}{R_{total}}=\frac{1}{3 \Omega}+\frac{1}{3 \Omega}+\frac{1}{3 \Omega}$

$\frac{1}{R_{total}}=3*(\frac{1}{3 \Omega})$

$R_{total}=1\Omega$

From our formula we know that the circuit power is:

$P=\frac{(50V)^2}{1\Omega}=2500 W$

Report an Error

Example Question #183 : Electricity

Consider a series circuit with a 18 V battery. The circuit is composed of three resistors, $R_1=10 \Omega, R_2 = 3 \Omega, R_3 = 7 \Omega$ . Calculate the power (units of Watts ) of the circuit.

Possible Answers:

32.4 W

108.0W

16.2 W

0.9 W

Correct answer:

16.2 W

Explanation:

We can write the power of a circuit as:

P=IV

This however, does not help much because we do not know the current in the circuit. But by Ohm's law:

$V=IR\Rightarrow I= \frac{V}{R}$

Substitution of this expression into the expression for power gives us:

$P = \frac{V^2}{R}$

Where $R= R_{tot}$ , the total resistance of the circuit. For a circuit in series, the total resistance is simply the sum of the resistors:

$R_{tot}=R_1+R_2+R_3 = (10+3+7) \Omega=20 \Omega$

Therefore, the power of the circuit is:

$P=\frac{(18V)^2}{20 \Omega}=16.2W$

Report an Error

Example Question #184 : Electricity

Calculate the power of a circuit composed of a 12V battery and three resistors in parallel. The resistors have resistance values of $R_1 = 10 \Omega, R_2 = 20 \Omega, R_3 = 5 \Omega$

Possible Answers:

50.35 W

0.34 W

4.20W

4.1 W

Correct answer:

50.35 W

Explanation:

The power of a circuit is given by:

P=IV .

By substitution of Ohm's law, we can show that:

$P=\frac{V^2}{R}$

Where $R=R_{tot}$ , or the total resistance of the circuit. For resistors in parallel, we add the inverses of their values. This is shown more plainly as:

$\frac{1}{R_{tot}}=\frac{1}{R_1}+\frac{1}{R_2}+\frac{1}{R_3}$

From the given values, we can calculate the total resistance as $R_{tot}=2.86 \Omega$ . This leads us to the final answer:

$P=\frac{(12V)^2}{2.86 \Omega}=50.35 W$

Report an Error

Example Question #141 : Circuits

You are given the following circuit powered by a 10V battery:

Circuit

$R1=5k\Omega$

$R2=8k\Omega$

$R3=12k\Omega$

Find the power supplied by the battery.

Possible Answers:

8mW

4mW

12mW

2.5mW

12mW

Correct answer:

4mW

Explanation:

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:

$R_{equivalent}=R1+\frac{R2*R3}{R2+R3}=5k\Omega+8k\Omega+12k\Omega=25k\Omega$

Then, to find power, you can use the following formula:

$P=IV=\frac{V^2}{R}=\frac{10^2}{25k\Omega}=4mW$

The battery supplies 4mW of power.

Report an Error

Example Question #254 : Electricity And Waves

How much power does a circuit produce if there is an equivalent resistance of $10 \Omega$ and a current of 2 A ?

Possible Answers:

400 W

100 W

200 W

20 W

40 W

Correct answer:

40 W

Explanation:

The equation for power in a circuit is given as:

$P = I^{2}R$

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:

$P = (2 A)^{2}(10\Omega ) = 40 W$

Report an Error

Example Question #187 : Electricity

A capacitor with a capacitance of 10 F stores 500 J of energy. What is the voltage across this capacitor?

Possible Answers:

100 V

20 V

10 V

500 V

50 V

Correct answer:

10 V

Explanation:

The correct answer is 10 V .

We can obtain this answer with the following equation regarding capacitors:

$U= \frac{1}{2}CV^{2}$

is the energy stored on the capacitor, is the capacitance, and is the voltage.

$(500J)=\frac{1}{2}(10F)(V^{2})$

Solving for we obtain:

V= 10 V

Report an Error

View AP Physics 1 Tutors

Jason
Certified Tutor

Brigham Young University, Bachelor, Neuroscience.

View AP Physics 1 Tutors

Mark
Certified Tutor

State University of New York at New Paltz, Bachelor of Science, Physics. State University of New York at New Paltz, Master of...

View AP Physics 1 Tutors

John
Certified Tutor

Arizona State University, Bachelor of Science, Microbiology.

All AP Physics 1 Resources

7 Diagnostic Tests 170 Practice Tests Question of the Day Flashcards Learn by Concept

Popular Subjects

MCAT Tutors in Los Angeles, LSAT Tutors in New York City, English Tutors in San Francisco-Bay Area, Calculus Tutors in San Francisco-Bay Area, Spanish Tutors in Seattle, Statistics Tutors in New York City, Spanish Tutors in San Francisco-Bay Area, ACT Tutors in San Francisco-Bay Area, ACT Tutors in Los Angeles, Physics Tutors in Chicago

Popular Courses & Classes

SSAT Courses & Classes in Boston, GRE Courses & Classes in Dallas Fort Worth, ACT Courses & Classes in Los Angeles, GMAT Courses & Classes in Miami, GRE Courses & Classes in Miami, GMAT Courses & Classes in New York City, LSAT Courses & Classes in Philadelphia, ACT Courses & Classes in Denver, SAT Courses & Classes in Denver, GMAT Courses & Classes in Boston

Popular Test Prep

ACT Test Prep in Denver, ISEE Test Prep in Phoenix, ACT Test Prep in Los Angeles, SAT Test Prep in Los Angeles, GRE Test Prep in Boston, GMAT Test Prep in Miami, LSAT Test Prep in San Francisco-Bay Area, GMAT Test Prep in San Diego, LSAT Test Prep in Boston, ACT Test Prep in New York City

DMCA Complaint

If you believe that content available by means of the Website (as defined in our Terms of Service) infringes one or more of your copyrights, please notify us by providing a written notice (“Infringement Notice”) containing the information described below to the designated agent listed below. If Varsity Tutors takes action in response to an Infringement Notice, it will make a good faith attempt to contact the party that made such content available by means of the most recent email address, if any, provided by such party to Varsity Tutors.

Your Infringement Notice may be forwarded to the party that made the content available or to third parties such as ChillingEffects.org.

Please be advised that you will be liable for damages (including costs and attorneys’ fees) if you materially misrepresent that a product or activity is infringing your copyrights. Thus, if you are not sure content located on or linked-to by the Website infringes your copyright, you should consider first contacting an attorney.

Please follow these steps to file a notice:

You must include the following:

A physical or electronic signature of the copyright owner or a person authorized to act on their behalf; An identification of the copyright claimed to have been infringed; A description of the nature and exact location of the content that you claim to infringe your copyright, in \ sufficient detail to permit Varsity Tutors to find and positively identify that content; for example we require a link to the specific question (not just the name of the question) that contains the content and a description of which specific portion of the question – an image, a link, the text, etc – your complaint refers to; Your name, address, telephone number and email address; and A statement by you: (a) that you believe in good faith that the use of the content that you claim to infringe your copyright is not authorized by law, or by the copyright owner or such owner’s agent; (b) that all of the information contained in your Infringement Notice is accurate, and (c) under penalty of perjury, that you are either the copyright owner or a person authorized to act on their behalf.

Send your complaint to our designated agent at:

Charles Cohn Varsity Tutors LLC
101 S. Hanley Rd, Suite 300
St. Louis, MO 63105

Or fill out the form below:

Do not fill in this field

Contact Information

* Full legal name

Company name

* Phone number

* Email address

Address

* Address1

Address2

* City

* State

* Zipcode

* Country

Complaint Details

* URL of copyrighted work (where your original material is located)

* Please describe the copyrighted work so that it may be easily identified

I am the owner, or an agent authorized to act on behalf of the owner of an exclusive right that is allegedly infringed.

I have a good faith belief that the use of the material in the manner complained of is not authorized by the copyright owner, its agent, or the law.

This notification is accurate.

I acknowledge that there may be adverse legal consequences for making false or bad faith allegations of copyright infringement by using this process.

* Signature (your digital signature is legally binding)

HIGH SCHOOL

GRADUATE SCHOOL

K-8

Search 50+ Tests

math tutoring

science tutoring

foreign languages

elementary tutoring

other

Search 350+ Subjects

AP Physics 1 : Circuit Power

Study concepts, example questions & explanations for AP Physics 1

All AP Physics 1 Resources

Example Questions

Example Question #21 : Circuit Power

Example Question #174 : Electricity

Example Question #175 : Electricity

Example Question #251 : Electricity And Waves

Example Question #252 : Electricity And Waves

Example Question #183 : Electricity

Example Question #184 : Electricity

Example Question #141 : Circuits

Example Question #254 : Electricity And Waves

Example Question #187 : Electricity

All AP Physics 1 Resources

Report an issue with this question

DMCA Complaint

Contact Information

Address

Complaint Details

Email address:
Your name:
Feedback: