Physics Comp 2021

If 10 J of work is used in pushing 1 C of charge into an electric field, its voltage relative to its starting position is

10 V.

A 4 ohm and a 6 ohm resistor are wired in series. What is their total (equivalent) resistance?

10 ohm

How much voltage is required to make 10 A of current flow through a 10 ohm resistor?

100 V

Coulombs Law says that the magnitude of the electrons force between any two charges depends

Inversely on the square of the distance between the charges and directly on the magnitude of the charges

The magnetic field inside a current-carrying coil will be greater if the coil encloses a(n)

Iron rod

When a current-carrying wire is bent into a loop, its magnetic field around the loop

Is concentrated and strengthens

Why does a magnet make other pieces of metal also magnetic?

It causes many of the electrons in the metal to spin in one direction

What role does Earth's magnetic field play in cosmic ray bombardment?

It deflects cosmic rays

A fundamental rule of electricity is that

Like charges repel each other; opposite charges attract each other

The force that acts between a pair of magnetic poles depends on

Magnetic pole strength, separation distance

Air is a great insulator, but if the charge on an object is high enough, electricity will travel through it.

True

As the number of branches in a parallel circuit is increased the overall resistance of the circuit is decreased.

True

Earth's magnetic South pole is near Earth's true geographic North pole.

True

Electric charges can be isolated but magnetic poles cannot.

True

Electric currents can induce a magnetic field.

True

In a parallel circuit, the voltage across every individual branch is equal.

True

In a series circuit the sum of the total voltage across a series circuit is equal to the sum of voltage drops across each individual resistor.

True

Light bulbs connected in series, all carry the same current, regardless of their resistances.

True

Magnetic field lines always form closed loops.

True

Magnetic field lines can never intersect.

True

Magnetic fields can induce an electric current.

True

Parallel circuits are characterized by the fact that there are multiple pathways by which charge can travel from the - terminal to the + terminal.

True

The Strong Nuclear Force holds an atom's nucleus together.

True

When charging an object by induction, the charged rod never touches that object that you are trying to charge.

True

Magnetic field lines about a current-carrying wire

circle the wire in closed loops

The electrical force between charges is strongest when the charges are

close together

An iron rod becomes magnetic when

the net spins of many of its electrons are aligned

I put two magnets next to each other and they fly away from each other for some reason. Why is that?

Same poles are facing each other.

A circuit in which each resistor has the same amount of current but different amounts of voltage must be a

Series circuit

What causes a magnetic field? (choose all that apply)

Spinning electrons, electrons moving in a current

If the electric field lines are drawn close to each other, then the field strength is _____ than when the lines are far apart.

Stronger

An object that has zero resistance to the movement of electrons at tempature s near absolute zero is known as a

Superconductor

A coil of wire with a current passing through it is an electromagnet.

True

A magnetic field is produced by the motion of charged particles.

True

There is an attractive force of 3.50 N between two point charges. What will the force be if the distance is increased to 5 times its original value?

0.140 N

A 60 W light bulb connected to a 120 V source draws a current of

0.5 A

A 4 ohm and 6 ohm resistor connected in parallel have a total resistance of

2.4 ohms

The current in two identical light bulbs connected in series is 0.25 A. The voltage across both bulbs is 110 V. The resistance of a single light bulb is

220ohms

The electric power supplied to a lamp that carries 2 A at 120 V is

240 watts

The power dissipated in a 4.0 ohm resistor carrying 3.0 A is

36 W.

A circuit has four parallel branches. The 1st has a 10 ohm resistor, the 2nd has a 50 ohm resistor, the 3rd has a 25 ohm resistor, and the 4th has a 5 ohm resistor. Which branch will have the highest amount of current flowing through it?

4th

The resistance of a filament that carries 2 A when a 10 V potential difference across it is

5 ohms

Which of the following will have a strong magnetic field around it?

A chunk of nickel with its domains aligned, a positive charged metal sphere that is moving, earth

Which of the following will have the strongest magnetic field? (Assume a current is flowing in the wire.)

A coil with 50 loops

​​​​​​I have a type of machine and I can't decide if it's a motor or a generator. I put in a battery and it starts to spin around. I have myself

A motor

All magnets have

A north and South Pole

In general, a permanent magnet has

A north and South Pole

The unit used that states the amount of current in a conductor is the

Ampere

Like kinds of magnetic poles repel while unlike kinds of magnetic poles

Attract

A main difference between gravitational and electric forces is that electrical forces

Attract and repel

The symbol used for magnetism is a

B

(Choose the BEST answer.) It is said that electric charge is conserved, which means that electric charge

Can be neither created nor destroyed

Voltage is the ratio of electric energy to the amount of electric

Charge

Magnetic field strength about a magnet is strongest where magnetic field lines are

Closer together

Objects can be charged by...

Contact, induction, friction or rubbing

Which would be an example of a good conductor?

Copper

The SI unit of charge is the...

Coulomb

Power is defined as the energy expended per unit of time. When translated to electrical terms, power is equal to

Current multiplies by voltage

As the magnitude of a charge decreases the magnitude of the electrostatic force will...

Decrease

Ohm's law tells us that the amount of current produced in a circuit is

Directly proportional to the voltage and inversely proportional to resistance.

The fundamental force underlying all chemical reactions is

Electrical force

Two protons attract each other gravitationally and repel each other electrically. The stronger of these two forces is

Electrical force

The subatomic particle that has a negative charge is a(n)

Electron

In solids, what is moved to cause an object to have a charge?

Electrons

A force exerted by a charged particle on another charged particle is a(n)

Electrostatic force

Electricity at rest is known as

Electrostatics

If you are in your car while it is struck by lightning you will be safe due to electrons being mutually repulsive called electron shielding.

False

The charge of a proton is greater than the charge of an electron

False

There are 5 fundamental forces in our universe.

False

In our Physics class, we analyze circuits by having the current flow

From negative terminal to the positive

Inside of a bar magnet, the magnetic field lines

Go from S to N

Electrically polarized objects

Have one positive side and one negative side

If you break a bar magnet in half, you'll

Have two magnets both with a North and South Pole

Just as water flows from a region of high pressure to a region of low pressure, electric charge flows from a region of

High electric potential energy to a region of low electric potential energy

Which of the following would increase the magnetic field around a coil of wire carry current?

Increase the number of coils

Place an iron rod inside a current carrying solenoid (looped wire) and you

Increase the strength of the electromagnetic

A positively charged ion has...

More protons than electrons

The source of all magnetism found in permanent magnets is

Moving electric charge

When animal fur is rubbed with a rubber rod, what charge is created on the rubber rod?

Negative charge

Who in 1820 showed that electricity and magnetism were related?

Oersted

Two charged particles held close together are released. As they move, the force on each particle increases. Therefore, the particles have....

Opposite signs

Static cling is the result of ______________.

Polarization

When silk is rubbed with a glass rod, what charge is created on the glass rod?

Positive charge

When plotting an electric field, a ____ is used.

Positive test charge

If you comb your hair and the comb becomes negatively charged, your hair becomes...

Positively charged

Which subatomic particle is has a greater mass?

Proton

In a parallel circuit what happens if the first branch burns out?

The current will continue to the next branch.

In a good insulator, the electrons are usually...

Tightly bound in place

Two parallel plates are oppositely charged. The left plate is negative and the right plate is positive. In which direction does the electric field point?

To the left

Surrounding every moving electron is

a magnetic field and an electric field

In units of measurement, power in watts is equal to

amperes x volts

A battery is needed in the circuit of your flashlight so that

an electric potential difference is maintained across the circuit

Direct current is normally produced by a

battery

Heat a copper wire and its electric resistance

increases

If two copper wires of the same length have different thickness, then the thicker wire has

less resistance

Wood does not have magnetic properties because it contains no

magnetic domains

A device that transforms electrical energy to mechanical energy is a

motor

A magnetic field will be produced by

moving electrons

The subatomic particle that has a positive charge is a(n)

proton

When the distance between two charges is halved, the electrical force between them

quadruples