AP Physics 2 : AP Physics 2

Study concepts, example questions & explanations for AP Physics 2

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Example Questions

Example Question #1 : Circuits

Combined circuit

 

In the circuit above, find the current through .

Possible Answers:

None of these

Correct answer:

Explanation:

First, find the total resistance of the circuit.

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

Next, add the series resistors together.

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

In series, all resistors will have the same current.

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

Example Question #2 : Ohm's Law

Combined circuit

In the circuit above, find the voltage drop across .

Possible Answers:

None of these

Correct answer:

Explanation:

First, find the total resistance of the circuit.

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

Next, add the series resistors together.

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

 and  will have the same voltage drop across them, as they are in parallel, and are equivalent to the combined resistor 

Example Question #4 : Circuits

Combined circuit

 

In the circuit above, find the voltage drop across .

Possible Answers:

None of these

Correct answer:

Explanation:

First, find the total resistance of the circuit.

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

Next, add the series resistors together.

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

and  will have the same voltage drop across them, as they are in parallel, and are equivalent to the combined resistor 

Example Question #1 : Ohm's Law

Three parallel resistors

 

 

 

 

What is the total resistance of the circuit?

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:

 

 

 

 

Example Question #3 : 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:

 

 

 

 

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 : 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

 

 

 

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