AP Physics 2 : Circuit Properties

Study concepts, example questions & explanations for AP Physics 2

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Example Questions

Example Question #11 : Ohm's Law

Three parallel resistors

 

 

What is the current flowing through ?

 

Possible Answers:

None of these

Impossible to determine

Correct answer:

Explanation:

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

 

 

We find that

 

, , and are in series. So we use:

 

 

 

 

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

 

 

 

 

 

Because and  are in parallel,

 

 

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

 

 

Using

 

 

Using algebraic subsitution we get:

 

 

Solving for

 

 

 

 

Example Question #11 : Circuits

Three parallel resistors

 

 

 

 

What is the current flowing through ?

 

Possible Answers:

None of these

Correct answer:

Explanation:

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

 

 

We find that

 

, , and  are in series. So we use:

 

 

 

 We will then find the total current of the circuit. This will also be the current of because this resistor is not in parallel with any others.

 

 

 

 

 

Example Question #13 : Ohm's Law

Three parallel resistors

 

 

 

 

What is the current flowing through ?

Possible Answers:

Impossible to determine

None of these

Correct answer:

Explanation:

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

 

 

We find that

 

, , and  are in series. So we use:

 

 

 

 

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

 

 

 

 

 

Because and  are in parallel,

 

 

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

 

 

Using

 

 

Using algebraic subsitution we get:

 

 

Solving for

 

 

 

 

Example Question #11 : Circuits

Three parallel resistors

 

 

What is the voltage drop across ?

Possible Answers:

None of these

Correct answer:

Explanation:

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

 

 

We find that

 

, , and  are in series. So we use:

 

 

 

 We will then determine the total current of the circuit.

 

 

 

 

Once again, using

 

 

Where  is the resistance of the resistor in question, we get

 

 

Example Question #12 : Circuits

Three parallel resistors

 

 

What is the voltage drop across ?

Possible Answers:

None of these

Correct answer:

Explanation:

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

 

 

We find that

 

, , and  are in series. So we use:

 

 

 

 

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

 

 

 

 

 

Because and  are in parallel,

 

 

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

 

 

Using

 

 

Using algebraic subsitution we get:

 

 

Solving for

 

 

 

 

Using

 

 

 

Example Question #13 : Circuits

Parallel circuit 1 jpeg

The current through is , has a resistance of . Determine the voltage of the battery.

Possible Answers:

Correct answer:

Explanation:

Due to the "loop rule", the voltage increase in the battery will need to be equal to the voltage drop in the resistor.

Use Ohm's law:

Combine equations:

Plug in values:

Example Question #11 : Circuit Properties

Parallel circuit 1 jpeg

If the battery has a voltage of , and has a resistance of , determine the current through .

Possible Answers:

Correct answer:

Explanation:

Due to the "loop rule", the voltage increase in the battery will need to be equal to the voltage drop in the resistor.

Use Ohm's law:

Combine equations:

Plug in values:

Example Question #11 : Circuits

A  battery is placed in series with five  resistors. Find the total resistance.

Possible Answers:

Correct answer:

Explanation:

In series, resistance adds conventionally.

Example Question #16 : Ohm's Law

A  battery is placed in series with five  resistors. Find the voltage drop across each resistor.

Possible Answers:

Correct answer:

Explanation:

In series, resistance adds conventionally.

Using Ohm's law for total current:

Now use Ohm's law for an individual resistor:

Example Question #17 : Circuits

A  battery is placed in series with five  resistors. Find the current.

Possible Answers:

Correct answer:

Explanation:

In series, resistance adds conventionally.

Using

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