Call Now to Set Up Tutoring:

(888) 888-0446

AP Physics 2 : Ohm's Law

Study concepts, example questions & explanations for AP Physics 2

Create An Account

All AP Physics 2 Resources

6 Diagnostic Tests 149 Practice Tests Question of the Day Flashcards Learn by Concept

Example Questions

Example Question #1 : Circuits

Parallel circuit 1 jpeg

$R_1=10\Omega$

$R_2=20\Omega$

V=25V

What is the current through the battery in the above circuit?

Possible Answers:

0.266A

30A

3.75A

10A

0.833A

Correct answer:

3.75A

Explanation:

First, find the total resistance of the circuit. Since the resistors are in parallel, use the following formula:

$\frac{1}{R1}+\frac{1}{R2}=\frac{1}{R_{total}}$

Plug in known values.

$\frac{1}{10\Omega}+\frac{1}{20\Omega}=\frac{1}{R_{total}}$

$R_{total}=6.66\Omega$

Next, use Ohm's law to find current.

V=IR

Plug in known values.

$I=\frac{25V}{6.66\Omega}=3.75A$

Report an Error

Example Question #1 : Circuits

There are 3 resistors in series. Their resistances are, in order, $2\Omega$ , $4\Omega$ , and $6\Omega$ . The total potential drop is 12V . What is the potential drop across the second resistor?

Possible Answers:

12V

Correct answer:

Explanation:

Use Ohm's law to find the current passing through each resistor. Because they are in series, they have the same amount of current. Once we get the current, we can plug in the resistance for each resistor to find its potential drop.

$I&=\frac{V_{tot}}{R_{tot}}$

$I=\frac{12V}{12\Omega}$

I= 1A

Now, find the potential drop across the $4\Omega$ resistor.

V&=IR

$V=(1A)(4\Omega)$

V= 4V

Therefore, the potential drop across the $4\Omega$ resistor is

Report an Error

Example Question #2 : Circuits

A 4.5V battery produces a current of 0.90A in a piece of copper wire. What is the resistance of the copper wire?

Possible Answers:

$3\Omega$

$6.4\Omega$

$5\Omega$

There's not enough information to find the resistance

$4.5\Omega$

Correct answer:

$5\Omega$

Explanation:

Even though there is no resistor, Ohm's law still applies. Use it to find the resistance of the wire.

$R&=\frac{V}{I}$

$R= \frac{4.5V}{0.90A}$

$R= 5\Omega$

The resistance of the copper wire is $5\Omega$

Report an Error

Example Question #1 : Circuits

Combined circuit

V_1 = V_2 = 4.5V

$R_1=R_3=R_4= 3\Omega$

$R_2=6\Omega$

In the circuit above, find the voltage drop across R_1 .

Possible Answers:

$\frac{9}{8}V$

None of these

4.5V

$\frac{9}{4}V$

Correct answer:

$\frac{9}{4}V$

Explanation:

First, find the total resistance of the circuit.

R_1 and R_2 are in parallel, so we find the equivalent resistance by using the following formula:

$\frac{1}{R_{1}}+\frac{1}R_{2}=\frac{1}{R_{1+2}}$

$\frac{1}{3}+\frac{1}{6}=\frac{1}{2}=\frac{1}{R_{1+2}}$

$R_{1+2}=2\Omega$

Next, add the series resistors together.

$R_{1+2}+R_3+R_4=R_{total}$

$R_{total}=8\Omega$

Use Ohm's law to find the current through the system.

V=IR

(V_1+V_2)=IR

$9V=I\cdot 8\Omega$

$I=\frac{9}{8}A$

Since R_1 and R_2 are in parallel, they will have the same voltage drop accross them.

$V_{1+2}=\frac{9}{8}A \cdot R_{1+2}$

$V_{1+2}=\frac{9}{8}A\cdot 2\Omega$

$V_{1+2}=\frac{9}{4}V$

Report an Error

Example Question #1 : Circuit Properties

Combined circuit

V_1 = V_2 = 4.5V

$R_1=R_3=R_4= 3\Omega$

$R_2=6\Omega$

In the circuit above, find the current through R_2 .

Possible Answers:

$\frac{3}{8}A$

None of these

$\frac{9}{8}A$

$\frac{3}{4}A$

Correct answer:

$\frac{3}{8}A$

Explanation:

First, find the total resistance of the circuit.

R_1 and R_2 are in parallel, so we find their equivalent resistance by using the following formula:

$\frac{1}{R_{1}}+\frac{1}R_{2}=\frac{1}{R_{1+2}}$

$\frac{1}{3}+\frac{1}{6}=\frac{1}{R_{1+2}}$

$\frac{3}{6}=\frac{1}{R_{1+2}}}$

$R_{1+2}=2\Omega$

Next, add the series resistors together.

$R_{1+2}+R_3+R_4=R_{total}$

$R_{total}=8\Omega$

Use Ohm's law to find the current in the system.

V=IR

(V_1+V_2)=IR

$9V=I\cdot 8\Omega$

$I=\frac{9}{8}A$

The current through R_1 and R_2 needs to add up to the total current, since they are in parallel.

$I_1 + I_2 =I_{total}$

$I_1 + I_2 =\frac{9}{8}A$

Also, the voltage drop across them need to be equal, since they are in parallel.

V_1=V_2

I_1R_1=I_2R_2

$I_1\cdot3\Omega=I_2\cdot 6\Omega$

Set up a system of equations.

$I_1\cdot3\Omega=I_2\cdot 6\Omega$

$I_1 + I_2 =\frac{9}{8}A$

Solve.

2I_2=I_1

$3I_2=\frac{9}{8}A$

$I_2=\frac{3}{8}A$

Report an Error

Example Question #2 : Circuits

Combined circuit

V_1 = V_2 = 4.5V

$R_1=R_3=R_4= 3\Omega$

$R_2=6\Omega$

In the circuit above, find the current through R_3 .

Possible Answers:

$\frac{9}{4}A$

None of these

$\frac{3}{4}A$

$\frac{3}{8}A$

$\frac{9}{8}A$

Correct answer:

$\frac{9}{8}A$

Explanation:

First, find the total resistance of the circuit.

R_1 and R_2 are in parallel, so we find their equivalent resistance by using the following formula:

$\frac{1}{R_{1}}+\frac{1}R_{2}=\frac{1}{R_{1+2}}$

$\frac{1}{3}+\frac{1}{6}=\frac{1}{R_{1+2}}$

$\frac{3}{6}=\frac{1}{R_{1+2}}}$

$R_{1+2}=2\Omega$

Next, add the series resistors together.

$R_{1+2}+R_3+R_4=R_{total}$

$R_{total}=8\Omega$

Use Ohm's law to find the current in the system.

V=IR

(V_1+V_2)=IR

$9V=I\cdot 8\Omega$

$I=\frac{9}{8}A$

In series, all resistors will have the same current.

Thus, the current through R_3 is the same as through the rest of the circuit.

Report an Error

Example Question #3 : Circuits

Combined circuit

V_1 = V_2 = 4.5V

$R_1=R_3=R4= 3\Omega$

$R_2=6\Omega$

In the circuit above, find the voltage drop across R_3 .

Possible Answers:

4.5V

None of these

$\frac{27}{8}V$

Correct answer:

$\frac{27}{8}V$

Explanation:

First, find the total resistance of the circuit.

R_1 and R_2 are in parallel, so we find their equivalent resistance by using the following formula:

$\frac{1}{R_{1}}+\frac{1}R_{2}=\frac{1}{R_{1+2}}$

$\frac{1}{3}+\frac{1}{6}=\frac{1}{R_{1+2}}$

$\frac{3}{6}=\frac{1}{R_{1+2}}}$

$R_{1+2}=2\Omega$

Next, add the series resistors together.

$R_{1+2}+R_3+R_4=R_{total}$

$R_{total}=8\Omega$

Use Ohm's law to find the current in the system.

V=IR

(V_1+V_2)=IR

$9V=I\cdot 8\Omega$

$I=\frac{9}{8}A$

R_1 and R_2 will have the same voltage drop across them, as they are in parallel, and are equivalent to the combined resistor $R_{1+2}$

$V=\frac{9}{8}A\cdot R_{3}$

$V=\frac{9}{8}A\cdot 3\Omega$

$V=\frac{27}{8}V$

Report an Error

Example Question #1 : Circuits

Combined circuit

V_1=V_2=4.5V

$R_1=R_3=R_4= 3\Omega$

$R_2=6\Omega$

In the circuit above, find the voltage drop across R_2 .

Possible Answers:

4.5V

$\frac{9}{8}V$

None of these

$\frac{9}{4}V$

Correct answer:

$\frac{9}{4}V$

Explanation:

First, find the total resistance of the circuit.

R_1 and R_2 are in parallel, so we find their equivalent resistance by using the following formula:

$\frac{1}{R_{1}}+\frac{1}R_{2}=\frac{1}{R_{1+2}}$

$\frac{1}{3}+\frac{1}{6}=\frac{1}{R_{1+2}}$

$\frac{3}{6}=\frac{1}{R_{1+2}}}$

$R_{1+2}=2\Omega$

Next, add the series resistors together.

$R_{1+2}+R_3+R_4=R_{total}$

$R_{total}=8\Omega$

Use Ohm's law to find the current in the system.

V=IR

(V_1+V_2)=IR

$9V=I\cdot 8\Omega$

$I=\frac{9}{8}A$

R_1 and R_2 will have the same voltage drop across them, as they are in parallel, and are equivalent to the combined resistor $R_{1+2}$

$V=\frac{9}{8}A\cdot R_{1+2}$

$V=\frac{9}{8}A\cdot 2\Omega$

$V=\frac{9}{4}V$

Report an Error

Example Question #1 : Ohm's Law

Three parallel resistors

R_1=R_4=R_5=2 ohms

R_2=5 ohms

R_3=6 ohms

What is the total resistance of the circuit?

Possible Answers:

$\frac{67}{13}\Omega$

$4\Omega$

$\frac{13}{15}\Omega$

None of these

$17\Omega$

Correct answer:

$\frac{67}{13}\Omega$

Explanation:

R_1 , R_2 , and R_3 are in parallel, so we add them by using:

$\frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3} = \frac{1}{R_{1,2,3}}}$

We find that $R_{1,2,3} = \frac{15}{13}\Omega$

$R_{1,2,3}$ , R_4 , and R_5 are in series. So we use:

$R_{1,2,3}+R_4 +R_5 = R_{total}$

$\frac{15}{13}\Omega+1\Omega +1\Omega = R_{total}$

$R_{total}=\frac{67}{13}\Omega$

Report an Error

Example Question #5 : Circuits

Three parallel resistors

$R_1=R_4=R_5=2\Omega$

$R_2=5\Omega$

$R_3=6\Omega$

What is the current flowing through R_3 ?

Possible Answers:

.560 amps

.398 amps

.650 amps

None of these

.375 amps

Correct answer:

.560 amps

Explanation:

R_1 , R_2 , and R_3 are in parallel, so we add them by using:

$\frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3} = \frac{1}{R_{1,2,3}}}$

We find that $R_{1,2,3} = \frac{15}{13}\Omega$

$R_{1,2,3}$ , R_4 , and R_5 are in series. So we use:

$R_{1,2,3}+R_4 +R_5 = R_{total}$

$\frac{15}{13}\Omega+1\Omega +1\Omega = R_{total}$

$R_{total}=\frac{67}{13}\Omega$

First, we need to find the total current of the circuit, we simply use:

V=IR

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

$I=\frac{15V}{\frac{67}{13}\Omega}$

$I=\frac{195}{67} amps$

Because R_1 , R_2 and R_3 are in parallel,

$I_1+I_2+I_3=I_{total}$

Also, the voltage drop must be the same across all three

V_1=V_2=V_3

Using

V=IR

I_1R_1=I_2R_2=I_3R_3

Using algebraic subsitution we get:

$I_3+I_3 \frac{R_3}{R_1}+I_3 \frac{R_3}{R_2}=I_{total}$

Solving for I_3

$\frac{I_{Total}}{1+\frac{R_3}{R_1}+\frac{R_3}{R_2}}=I_3$

$\frac{I_{Total}}{1+\frac{6}{2}+\frac{6}{5}}=I_3$

.560 amps=I_3

Report an Error

View Tutors

Rebecca
Certified Tutor

Lee College, Bachelor in Arts, Religious Studies.

View Tutors

Michael
Certified Tutor

Virginia State University, Master of Science, Special Education.

View Tutors

Juan
Certified Tutor

University of Central Florida, Bachelor of Science, Business, General.

All AP Physics 2 Resources

6 Diagnostic Tests 149 Practice Tests Question of the Day Flashcards Learn by Concept

Popular Subjects

Chemistry Tutors in Miami, Reading Tutors in Los Angeles, Biology Tutors in Miami, Calculus Tutors in Phoenix, Chemistry Tutors in Philadelphia, Math Tutors in Los Angeles, Physics Tutors in Miami, ISEE Tutors in Houston, French Tutors in Philadelphia, GRE Tutors in Miami

Popular Courses & Classes

SSAT Courses & Classes in New York City, SSAT Courses & Classes in Denver, ISEE Courses & Classes in Washington DC, SSAT Courses & Classes in Boston, ACT Courses & Classes in Miami, GMAT Courses & Classes in Philadelphia, ACT Courses & Classes in Chicago, Spanish Courses & Classes in Atlanta, GRE Courses & Classes in San Francisco-Bay Area, ACT Courses & Classes in Los Angeles

Popular Test Prep

LSAT Test Prep in Washington DC, GRE Test Prep in Houston, GRE Test Prep in New York City, SSAT Test Prep in Phoenix, ACT Test Prep in Denver, GRE Test Prep in Philadelphia, ISEE Test Prep in Houston, GRE Test Prep in San Francisco-Bay Area, ACT Test Prep in San Diego, MCAT Test Prep in Chicago

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 2 : Ohm's Law

Study concepts, example questions & explanations for AP Physics 2

All AP Physics 2 Resources

Example Questions

Example Question #1 : Circuits

Example Question #1 : Circuits

Example Question #2 : Circuits

Example Question #1 : Circuits

Example Question #1 : Circuit Properties

Example Question #2 : Circuits

Example Question #3 : Circuits

Example Question #1 : Circuits

Example Question #1 : Ohm's Law

Example Question #5 : Circuits

All AP Physics 2 Resources

Report an issue with this question

DMCA Complaint

Contact Information

Address

Complaint Details

Email address:
Your name:
Feedback: