All AP Physics 1 Resources
Example Questions
Example Question #31 : Electrostatics
By how much will the electric field change if the charges of all source charges are increased by a factor of , and the test charge is increased by a factor of ?
The electric field will be changed by a factor of
The electric field will be changed by a factor of
The electric field will be changed by a factor of
The electric field will be changed by a factor of
The electric field will be changed by a factor of
The electric field for point charges is given by:
Where is Coulomb's constant, is the charge of each source charge , is distance of the test charge from the source charge, and is the number of source charges.
In this problem, since all of the source charges are increased by a factor of 2, the electric field will also increase by a factor of 2. The increase in the charge of the test charge is not applied to the strength of the electric field, since the electric field is only dependent on the values and locations of the source charges.
Example Question #1 : Fundamentals Of Electric Charge
Two identical conducting spheres are attached to insulated posts and charged so that and .
The spheres are brought together so they touch, then moved back apart. What is the charge on now?
When the spheres make contact, charges are exchanged. The charges on the spheres will move due to the Coulomb forces from all the particles in each sphere. They will move toward equilibrium.
In this case has a net negative charge while has a net positive charge. will have to migrate to so that .
When the spheres are separated they will have equal charge and the charge on will still be .
Example Question #101 : Electricity And Waves
Determine the total electric charge of molecules in solution in Coulombs.
In solution, the ions will disassociate into and . Since there will be molecules of with a total charge and molecules of with a total charge of , the overall charge will be
Example Question #31 : Electrostatics
Consider the given diagram of two electrical charges. Which of the following is true about charges A and B?
A is negative and B is positive
A is positive and B is negative
Both charges are negative
Both charges are positive
Both charges are positive
In this question, we're presented with a diagram in which two electrical charges have field lines pointing away from them. We're then asked to determine a true statement regarding these two charges.
To be able to answer this question correctly, we'll have to recall that for positive electrical charges, the field lines will always point away from the charge. For negative electrical charges, the field lines point inwards toward the charge. Since both charges A and B in the diagram have their field lines pointing away from them, both of them must be positively charged. Also notice that their field lines will not cross one another; instead, they are repelled from one another.
Example Question #4 : Fundamentals Of Electric Charge
An electric field line is point from the left towards the right. Where will an electron move when placed in the field?
It will not move
Downward
Upward
Towards the right
Towards the left
Towards the left
The electron will move towards the left because electric field lines always point towards the negative charge. The electron is negatively charged and will oppose the negative electric field on the right and move towards the positive end on the left.
Therefore the correct answer is that the electron will move to the left.
Example Question #36 : Electrostatics
A point charge of coulombs experiences a force of in an electric field. What is the magnitude of this electric field?
The formula for the force on a point charge in an electric field is as follows:
is the force on the charge, is the magnitude of the charge and is the electric field. Substituting for our values we obtain:
Therefore the correct answer is