All High School Physics Resources
Example Questions
Example Question #101 : Electricity And Magnetism
The resistivity of most common metals __________________ .
remains constant over wide temperature ranges
decreases as the temperature increases
varies randomly as the temperature increases
increases as the temperature increases
increases as the temperature increases
At higher temperature, the atoms are moving more rapidly and are arranged in a less orderly way. Therefore it is expected that these fast moving atoms are more likely to interfere with the flow of electrons. If there is more interference in the flow of electrons, then there is a higher resistivity.
Example Question #2 : Resistivity
Which Resistors are connected in parallel?
and
All answer choices are correct
None of the answer choices are correct
and
and
and
Resistors are in parallel when the electric current passes through two or more branches or connected parts at the same time before it combines again. After the current leaves the battery it travels to . Then the current splits and travels between the other two resistors before the current coming back together and connecting back to the battery.
Example Question #102 : Electricity And Magnetism
How does adding resistors in parallel affect the overall current of the circuit?
The current increases
The current stays the same
The current decreases
The current increases
Adding resistors in parallel decrease the overall equivalent resistance as they are added using the equation
Since the overall equivalent resistance is decreased, if the voltage is constant the overall current would increase.
Therefore
This shows the inverse relationship between the two values.
Example Question #25 : Resistors
Which resistor has the greatest current going through it?
Assume all the resistors are equal.
and
and
As we examine the circuit we first come across the first two resistors. These resistors are in parallel. In parallel circuits, the current splits to go down each branch. In this case, the resistors are of equal value meaning that the current is split evenly between the two.
We then come across another parallel branch with two resistors on one side and a single resistor on the other side. The two resistors in series add up to create more resistance on the top branch. The single resistor on its own has less resistance.
Since current always chooses the path of least resistance, more current will flow through the single resistor, than through the branch with two resistors in series.
Therefore, would have the greatest resistance flowing through it.
Example Question #101 : Electricity And Magnetism
Calculate the current through the 10 ohm resistor.
To begin, let us start with the resistor and the resistor that are in parallel. In parallel we can add resistors through the equation
This new resistor is now in series with the two resistors. In series we can just add these resistors up.
This new resistor is now in parallel with the resistor. In parallel we can add resistors through the equation
This new resistor is now in series with the and resistor. In series we can just add these resistors up.
Now that we have the equivalent resistance of the circuit. We can now determine the current flowing out of the battery.
Rearrange to solve for current.
One of the best ways to work through a problem like this is to create a V= IR chart for all the components of the circuit.
We know that the current that is flowing out of the battery is the current that is flowing through both by 5 and 3 Ohm resistors since all of these are in series. So we can put this information into our chart.
Using Ohm’s Law we can determine the voltage for each of these two resistors.
We can now use Ohm’s law and our voltage to determine the current going through the 14 Ohm resistor.
Next we can analyze the current in the Junction between the 5, 14 and 4 Ohm resistors. Kirchoff’s laws state that the sum of the current flowing in and out of junction must equal 0.
We have flowing in from the resistor and flowing out to go through the resistor.
So the current going through the 4 Ohm resistor is 3 amps. This will be the same for both 4 ohm resistors as both have the same current going into and out of the junctions near them. We can then use this to determine the voltage drop across each of the resistors.
Now let’s add this to our chart.
We can now use Kirchoff’s loop law to determine the voltage across the 10 Ohm resistor. Let’s analyze the loop that goes from the 5, to the 4 to the 10 back through the 4 and then through 3 Ohm resistor.
We can now use Ohm’s Law to determine the current through the 10 Ohm resistor.
Example Question #102 : Electricity And Magnetism
Calculate the current in the 15 Ohm Resistor.
To begin, let us start with the resistor and the resistor that are in parallel. In parallel we can add resistors through the equation
This new resistor is now in series with the two resistors. In series we can just add these resistors up.
This new resistor is now in parallel with the resistor. In parallel we can add resistors through the equation
This new resistor is now in series with the and resistor. In series we can just add these resistors up.
Now that we have the equivalent resistance of the circuit. We can now determine the current flowing out of the battery.
Rearrange to solve for current.
One of the best ways to work through a problem like this is to create a V= IR chart for all the components of the circuit.
We know that the current that is flowing out of the battery is the current that is flowing through both by 5 and 3 Ohm resistors since all of these are in series. So we can put this information into our chart.
Using Ohm’s Law we can determine the voltage for each of these two resistors.
We can now use Kirchoff’s loop law through the loop of the 5, 3, and 14 Ohm resistor to determine the voltage that is traveling through the 14 Ohm resistor.
We can now use Ohm’s law and our voltage to determine the current going through the 14 Ohm resistor.
We can now add this information to our chart.
Next we can analyze the current in the Junction between the 5, 14 and 4 Ohm resistors. Kirchoff’s laws state that the sum of the current flowing in and out of the junction must equal 0.
We have 4A flowing in from the 5 Ohm resistor and 1A flowing out to go through the 14 Ohm resistor.
So the current going through the 4 Ohm resistor is 3 amps. This will be the same for both 4 ohm resistors as both have the same current going into and out of the junctions near them. We can then use this to determine the voltage drop across each of the resistors.
Now let’s add this to our chart.
We can now use Kirchoff’s loop law to determine the voltage across the 10 Ohm resistor. Let’s analyze the loop that goes from the 5, to the 4 to the 10 back through the 4 and then through 3 Ohm resistor.
We can now use Ohm’s Law to determine the current through the 10 Ohm resistor.
We can now add this information to our chart.
We can now analyze the junction between the 4, 10 and 15 Ohm resistor.
Kirchoff’s laws state that the sum of the current flowing in and out of the junction must equal 0.
We have 2A flowing in from the 4 Ohm resistor and 1.2A flowing out to go through the 10 Ohm resistor.
Example Question #103 : Electricity And Magnetism
Calculate the current through the 6 ohm resistor.
To begin we need to simplify the circuit to get the equivalent resistance. Let’s start with the 3 and 6 Ohm resistors in parallel.
Now we can add this resistor to the 4 Ohm resistor as they are in series.
We can now determine the current coming out of the battery using Ohm’s Law.
Rearrange to solve for current.
The current coming out of the battery will be the same current that moves through the 4 Ohm resistor. So we can determine the voltage drop across the 4 ohm resistor.
We can then use Kirchoff’s loop law to determine the voltage drop across the 6 Ohm resistor. Let’s analyze the loop that goes from the battery to the 4 ohm resistor and through the 6 ohm resistor.
Example Question #961 : High School Physics
Calculate the voltage drop across the 4 ohm resistor.
To begin we need to simplify the circuit to get the equivalent resistance. Let’s start with the 3 and 6 Ohm resistors in parallel.
Now we can add this resistor to the 4 Ohm resistor as they are in series.
We can now determine the current coming out of the battery using Ohm’s Law.
Rearrange to solve for current.
The current coming out of the battery will be the same current that moves through the 4 Ohm resistor. So we can determine the voltage drop across the 4 ohm resistor.
Example Question #104 : Electricity And Magnetism
Kirchoff’s junction rule is an example of
None of the givens answers
Conservation of charge
Conservation of momentum
Conservation of energy
Conservation of charge
Kirchoff’s loop rules states the sum of the current going into and out of the junction must equal 0. In other words, the current going in must equal the current going on. Current is a measure of the flow of charge. Therefore, this law is conservation of charge as the number of electrons going into a junction must equal the number of electrons flowing out.
Example Question #105 : Electricity And Magnetism
Calculate the voltage drop across the 14 ohm resistor.
To begin, let us start with the resistor and the resistor that are in parallel. In parallel we can add resistors through the equation
This new resistor is now in series with the two 4Ω resistors. In series we can just add these resistors up.
This new resistor is now in parallel with the resistor. In parallel we can add resistors through the equation
This new resistor is now in series with the and resistor. In series we can just add these resistors up.
Now that we have the equivalent resistance of the circuit. We can now determine the current flowing out of the battery.
Rearrange to solve for current.
One of the best ways to work through a problem like this is to create a V= IR chart for all the components of the circuit.
We know that the current that is flowing out of the battery is the current that is flowing through both by 5 and 3 Ohm resistors since all of these are in series. So we can put this information into our chart.
Using Ohm’s Law we can determine the voltage for each of these two resistors.
We can now use Kirchoff’s loop law through the loop of the 5, 3, and 14 Ohm resistor to determine the voltage that is traveling through the 14 Ohm resistor.
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