Title: Pre-Unit Assessment
Course: MNPCC Physics > Section: Electricity and Magnetism

Use this quiz to see where you are at as you head into the unit.

Q: Two balloons are rubbed on a person's head and then suspended from a string.  The balloons are brought close together.  What will happen with the balloons?
- They will repel each other because they have the same charge. (Correct)
- They will attract each other because they have the same charge. (Likes repel.)
- They will repel each other because they have opposite charges. (They are charged in the same manner, so they have the same charge. If they did have opposite charges they would attract.)
- They will attract each other because they have opposite charges. (They are charged in the same manner, so they have the same charge.)
A: They will repel each other because they have the same charge.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: Which of the following is needed to have a complete electrical circuit and for charge to flow?
- A closed circuit made of conducting material. (Correct.)
- An open circuit made of insulating material. (Open means there is a break in the circuit.)
- A closed circuit made up of insulating material. (By definition charge cannot flow through insulators.)
- An open circuit made of insulating material. (Open means there is a break, and insulators do not let charge flow.)
A: A closed circuit made of conducting material.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: What happens to the amount of charge flow(current) as the potential difference (voltage) increases?
- It increases. (Correct.)
- It decreases. (It is a direct relationship.)
- It remains the same. (There is a direct relationship.)
A: It increases.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: The diagram below illustrates two different types of circuits, one series and on parallel.  Both are initially set up so both bulbs light in both circuits.  What will happen if one of the bulbs from each setup is removed, and no other rearrangement is done to close the gaps created?
- Only the other bulb in the series circuit will go out.  The remaining bulb in the parallel circuit will remain lit. (Correct.)
- Both of the remaining bulbs in the circuits will go out. (The remaining parallel bulb still has a complete circuit.)
- Both of the remaining bulbs will remain lit. (The series bulb will no longer have a complete circuit.)
- Only the remaining bulb in the series circuit will remain lit.  The bulb in the parallel circuit will go out. (This is backwards.)
A: Only the other bulb in the series circuit will go out.  The remaining bulb in the parallel circuit will remain lit.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: In the situations below each circuit is going from having one bulb to having two bulbs.  What will happen to the amount of current in the circuit in each situation?
- The current will go down in situation A and up in situation B. (Correct.)
- The current will go up in situation A and down in situation B. (Opposite.)
- The current will go down in both situations. (It will only go down in one of them.)
- The current will go up in both situations. (It will only go up in one of them.)
A: The current will go down in situation A and up in situation B.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: Two magnets are brought near each other and they attract one another.  What would their behavior be if one of the magnets was flipped over?
- They would repel each other. (Correct.)
- They would attract each other. (The opposite poles would be aligned.)
- They would no longer interact with each other. (The interaction is permanent.)
A: They would repel each other.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: A compass is set under a wire that is running in a North-South direction.  The wire is then hooked up in a circuit so that current go through it as shown.  What will happen to the compass?
- It will rotate perpendicular to the wire. (Correct.)
- It will stay aligned as it currently is. (Magnetic fields are always perpendicular to current flow.)
- It will turn completely around. (Magnetic fields are always perpendicular to current flow.)
A: It will rotate perpendicular to the wire.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: What will happen when a strong magnet is dropped through a copper tube?
- The magnet will interact with the tube causing its fall to slow. (Correct.)
- There will be no interaction between the magnet and the tube. (Magnets moving with respect to any conductor will interact with the conductor.)
- The magnet will interact with the tube causing its fall to speed up. (This would lead to perpetual motion machines, so no.)
A: The magnet will interact with the tube causing its fall to slow.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: What happens to the power output of a light bulb if it has 60 volts across it instead of the usual 120?
- It will be cut in half. (Correct.)
- It will double. (It is a direct relationship.)
- It will go down by a factor of four. (It is not a squared relationship.)
- It will go up by a factor of four. (Wrong direction and not a squared relationship.)
A: It will be cut in half.
If right: Your answer is correct.
If wrong: Your answer is incorrect.