Electricity and Magnetism - Non-Contact Forces and Fields

Practice flashcards covering non-contact forces, gravitational, electric, and magnetic fields, magnetization/demagnetization, and key magnet concepts.

What is a force?

A push or pull on an object that can cause it to move; forces are present around every object in the universe.

What is a non-contact force?

A force that can act on an object without touching it (examples include magnetic, gravitational, and electric forces).

Which three non-contact forces are discussed in this unit?

Magnetic Force, Gravitational Force, and Electric Force.

What is a gravitational force field?

The region around an object where gravity can pull on other objects; shown by lines of force; strength depends on distance and mass.

What is weight?

The force of gravity acting on an object.

What is mass?

The amount of matter in an object; the number of atoms inside it.

How does distance affect gravitational force?

The closer two objects are, the stronger the gravitational force; farther apart, the weaker the force.

How does mass affect gravitational force?

More mass means a stronger gravitational force; less mass means a weaker force.

What evidence shows gravitational fields exist?

The Earth and Moon attract each other; the Moon orbits the Earth due to gravity.

What is an electric force field?

An invisible region around electrically charged objects where electric forces act; field lines point away from positive charges and toward negative charges.

What affects the strength of the electric field?

Distance between charges (closer = stronger; farther = weaker) and the magnitude of the charges.

What is a magnetic force field?

The invisible region around magnets where magnetic forces act; field lines indicate direction and strength; Earth’s core creates a planetary magnetic field.

Where do magnetic field lines begin and end around a bar magnet outside?

They begin at the North pole and travel outward to the South pole; inside the magnet they complete the loop from South to North.

What are magnetic poles?

The North and South ends of a magnet where the magnetic force is strongest.

What happens when opposite poles are near each other?

Opposite poles attract.

What happens when like poles are near each other?

Like poles repel.

Which metals are commonly attracted to magnets?

Iron, nickel, and cobalt (not all metals are attracted).

What are the main types of magnets?

Permanent magnets, Temporary magnets (magnetized objects), and Electro magnets.

What is magnetization?

The process of turning a material into a temporary magnet by aligning its magnetic domains in the same direction, often by rubbing with a magnet in the same direction.

What is demagnetization?

The loss of a magnet's magnetic strength, caused by heating, hammering, or dropping; permanent magnets are harder to demagnetize.

What are magnetic domains?

Regions where atomic magnetic fields align; in magnets most domains point the same direction, giving a net magnetic field; in non-magnets domains point randomly.

Can a magnet exert force on another object without touching it?

Yes, through its magnetic field; magnets attract or repel across a distance.

What happens to field lines between unlike poles?

Field lines connect from the North pole of one magnet to the South pole of the other, showing attraction.

What evidence demonstrates electric force fields exist besides lab demonstrations?

Static electricity (balloons, shocks), lightning, and other charge-related phenomena demonstrate electric fields.

What is an electromagnet?

A magnet created by an electric current producing a magnetic field, typically using a coil of wire around a core.