Science Quiz on January 25th

When clothes are run through the dryer they often become charged and stick together. What causes the charges to seperate?

A force, such as friction, causes the charges to seperate. A positively charged object and a negatively charged object attract each other. Similarly charged objects repel.

Which of these is an example of a force that acts at a distance?

A magnet is pushed away when it is brought near the end of another magnet.

Which of these best describes electric charge?

A particle that moves freely through matter and causes static electricity to build up on objects.

Would moving the coil back and forth instead of the magnet produce the same effect?

An electric current is induced when either the magnet or the wire is moving.

How is this example of static electricity related to lightning during a thunderstorm?

During the thunderstorm, friction between water and ice molecules in the clouds creates an electric imbalance: static electricity. The bottom of the clouds becomes negatively charged and is attracted to the more positively charged surface of Earth. Lightning or electric discharge occurs when the negative charges flow toward Earth.

If two magnets were cut in half along the line between the red and blue paint, which statement would describe the four bars that are produced?

Each piece would have a north pole and south pole

Predict what would happen if the entire unit is moving, but the magnet and coil are not moving relative to each other.

For electromagnet induction to occur, the magnet and the wire must be moving relative to each other. If both the magnet and wire are moving back and forth together, there will be no electric induction because they are moving at same velocity (speed and direction).

All charged objects create an electric field around them. What two factors determine the strength of two electric fields upon the charged objects creating them?

How charged the object creating the field is and the distance between the two charged objects.

Which of these best describes how a powerful electromagnet could be used in a junkyard?

It could move heavy objects made of iron.

Joe has an idea to cut a bar magnet in half so that he can have one magnet with a north pole and one magnet with a south pole. What is wrong with this idea?

It is impossible to create a magnet with only one magnetic pole.

What is the effect of moving the magnet back and forth inside the coiled wire?

Moving a magnet back and forth within a solenoid (coiled wire) causes electromagnet induction, which produces an electric current.

Definition of static electricity.

Static electricity is caused by an imbalance of electric charge. It is called "static" because the charges are not moving or flowing.

Two balloons charged with static electricity move away from each other when placed side-by-side. Which statement best explains this phenomenon?

The balloons have like electric charges, creating a repulsive electric force.

What would be the effect of bringing a negatively-charged metal ball near an iron ball?

The bar would become positively charged and attract the metal ball.

An ammeter is used to measure the current in a wire. If an ammeter indicates a current in a wire, what can be said about the charges in the wire?

The charges are moving through the wire.

How does an increase in the amount of charge flowing through an electromagnet change the current and the magnetic force generated by the current?

The charges within the current move faster and the magnetic force increases.

The permanent magnet is being moved toward the wire. If the permanent magnet is accelerated as it moves toward the wire, what will happen to the induced current in the wire?

The current increases as the magnet moves faster.

Describe ways to increase the amount of electric current in this setup.

The electric current can be increased by increasing the speed at which the magnet and wire move relative to each other, increasing the strength of the magnet, or increasing the number of coils in the wire.

Two particles are moving toward one another. Both of the particles have a strong positive charge. As they move toward one another, how will the electric force between the two particles change?

The electric force between the two particles will become repulsive and the objects will repel each other.

Which of the following is the best explanation for Diagram A?

The field lines connect the objects due to an attractive force.

Which of the following is the best explanation for Diagram B?

The field lines diverge due to a repulsive force.

Why are certain materials, such as copper and aluminum, not magnetic?

The magnetic fields of the individual atoms that make up the materials cancel each other out.

The electromagnet and permanent magnet are equal in strength. How could the force between the two magnets be increased?

The magnets could be moved closer together, the number of loops in the electromagnet could be increased.

Where is the magnitude of force around this object the greatest? (horseshoe magnet)

The magnitude is greatest close to the poles.

The end of one bar magnet is placed near the end of another bar magnet. The two ends seem to push each other apart. Which of these statements is true?

The two ends are like poles.

Packing peanuts question:

The will be pushed away from the wool cloth.

Why do the rings in the photo levitate instead of simply falling.

There is a magnetic force acting on them which forces the rings to repel.

Which statement describes the current on the surface of a balloon that is charged with static electricity?

There is no current because the charges are not moving.

If the permanent magnet were to be doubled in size and then places so that it was touching the loop of wire, what statement could be said about the current in the loop of wire?

There would be no current in the wire due to the stationary magnet.

Which of the following sets of objects would produce field lines similar to those in Diagram A?

Two magnets with the N and S poles facing each other, two oppositely charged objects

Touching the doorknob sent a shock to the person's hand. What is this called, and what is happening with the charges?

Upon contact, the extra negative charges leave the person and move to the relatively positive charged doorknob. This is called an electric discharge.

A student learns that an LED bulb will light up when it is in the electric field of a plasma globe. What steps will help the student map and model the field during an experiment?

Walk around the globe recording where the LED bulb lights up, move the LED bulb closer to the plasma globe until it lights up, measure the distance between the glowing LED bulb and the plasma globe

How is electromagnetism is used to make a crane operate.

Within the magnet, there is an interaction between electricity and magnetism which forms an electromagnet. There is an electric current which contains charges that overlap. This creates a magnetic field. The metal scraps are attracted to the magnet when the electromagnet is turned on.

Explain how you could increase the amount of current induced in a wire.

You could increase the strength of the magnet, the number of loops in the wire, and how quickly you move the magnet through the wire.

electromagnet definition

a coil of wore around an iron core

electric current definiton

a continuous flow of electric charges from one region to another

electric force definition

a force of attraction or repulsion between objects due to their charges

electric charge definition

a physical property of all matter -every type of electricity is a result of electric charge

The plasma streams inside the globe are evidence that an electric field...

acts throughout the globe

Which object would be attracted by a magnet?

an iron nail

magnet definition

an object that attracts, or pulls on, materials that contain iron or other metals

An electric field acts on objects...

at a distance

Sometimes the north and south poles of atoms in a material will line up. What is the term for the region where this occurs?

domain

The interaction between electric energy and magnetism has been an important topic in 20th-century science. Which term describes this interaction?

electromagnetism

Moving two magnetic objects closer together will ______ increase the strength of the magnetic force between them.

increase

Which of these is a ferromagnetic material?

iron

Daniel has a long piece of copper wire. He shapes the wire into a coil. What could Daniel do to create an electric current in the wire?

move a bar magnet in and out of the wire coil

An object is most likely to become electrically charged by gaining or losing which type of particles?

negative particles

The magnetic field is ___ near the poles of the magnet.

strongest

electric field definition

the area around a charged object in which another charged object is affected by the electric force

magnetic field definition

the area around a magnet in which magnetic forces affect magnetic objects

field definition

the area in which an object experiences a force that acts at a distance

gravitational field definition

the area surrounding an object in which another object is pulled toward the object

electromagnetism definition

the interaction between electricity and magnetism

magnetic domain definition

the north poles of groups of atoms can line up in the same direction in areas examples- iron, nickel, cobalt (ferromagnetic materials)

magnetic forces definition

the push or pull exerted by magnets

Which statements describe the iron-containing rock and the nails?

the rock is a magnet, the nails are attracted to magnets, most of the magnetic domains in the rock are aligned with each other