Electricity and Magnetism

Electricity and Magnetism

Test Review

Multiple Choice

Multiple Select

Select the two variables that determine the gravitational force between two objects

• mass

• volume

• magnetism

• distance

Multiple Choice

• The electrons will pass to the foam cup but will remain in a localized, positively charged area on the cup where the rod was placed.

• The electrons will pass to the foam cup but will remain in a localized, negatively charged area on the cup where the rod was placed.

• The electrons will pass from the foam cup to the aluminum can, and both the foam cup and the aluminum can will become positively charged.

• The electrons will pass from the foam cup to the aluminum can, and both the foam cup and the aluminum can will become negatively charged

Multiple Choice

Which statement correctly describes the factors affecting gravitational force between two objects?

• Gravitational force between two objects is determined by their masses and the distance between their outermost edges

• Gravitational force between two objects is determined by their masses and the distance between their centers.

• Gravitational force between two objects is determined by their volumes and their acceleration relative to the Sun.

• Gravitational force between two objects is determined by their diameters and their distance from the Sun.

Multiple Choice

The Sun is the center of our solar system, which includes planets, dwarf planets, asteroids, and comets. Which statement best explains why all objects, including planets, orbit the Sun, instead of the Sun orbiting one or more planets?

• Planets have less mass than the Sun.

• The Sun rotates faster than any of the planets.

• The Sun formed before the planets or other objects.

• Planets are further from the center of the solar system.

Multiple Choice

What is produced by a stream of electrons flowing through a wire that is coiled around an iron core?

• an atomic field

• a radiation field

• a magnetic field

• a static field

Multiple Choice

A student claims that Earth has a magnetic field. Which evidence would best support the student's claim?

• The student creates a working circuit that illuminates a bulb using wire and a battery.

• The student turns in all directions with a compass and the needle always points north.

• The student receives a shock after walking across the carpet and touching a doorknob.

• The student rolls a ball down a large hill and the ball comes to a complete stop at the bottom.

Multiple Choice

A group of students plans to make a small compass using a blunt sewing needle. What is the next step they should perform with the needle?

• press it between two hard surfaces

• heat it on a candle flame

• rub it on a bar magnet

• scratch it on a steel spoon

Multiple Choice

Which statement about conductors and insulators charging is correct?

• Both conductors and insulators charge through friction.

• Both conductors and insulators charge through induction.

• Conductors charge through induction, whereas insulators charge through friction.

• Conductors charge through friction, whereas insulators charge through induction.

Multiple Choice

• The balloons will hang at a greater elevation, because they will have greater charges so the force of electrical repulsion between them will be greater.

• The balloons will hang at a smaller elevation, because more thoroughly rubbing them will more completely remove their charges, reducing the electrical repulsion between them.

• The balloons will hang at the same elevation, because electrical repulsion is an unvarying phenomenon which results from the existence of charge and not its quantity.

• The balloons will hang straight down or more closely together, because a larger number of rubs with fur will give them opposite rather than like electrical charges.

Multiple Choice

• They move to the top of both cans.

• They move to the bottom in both cans.

• They move from the right can to the left can.

• They move from the left can to the right can.

Multiple Choice

• Balloon 1, only

• Plastic sheet 1, only

• Balloon 1 and Plastic sheet 2

• Balloon 2 and Plastic sheet 1

Multiple Choice

• It will distribute itself evenly over the surface of the sphere, because like charges repel and the sphere is a conductor.

• It will remain at the point of contact between the rod and the sphere, because resistance in the metal prevents the charges from easily moving.

• It will quickly spread to the air around the sphere, because it will seek to occupy as large a volume of neutral matter as possible.

• It will slowly drift to the bottom of the sphere, because the charges rapidly attach to individual atoms, making them slightly heavier than surrounding atoms.

Multiple Choice

• She should place a negatively charged rod near the left sphere.

• She should place a positively charged rod near the left sphere.

• She should place two negatively charged rods near each sphere.

• She should place two positively charged rods near each sphere.

Multiple Choice

When a plastic rod is rubbed with a wool cloth, the wool acquires a positive charge. What is the best explanation for this effect?

• protons are transferred to the cloth

• protons are transferred to the rod

• electrons are transferred to the cloth

• electrons are transferred to the rod

Multiple Choice

Markeisha needs to create an electromagnet for her science project. She needs to create a magnet that can pick up iron filings out of a mixture of substances. Which list of materials would best help Markeisha build her electromagnet?

• string, battery, metal nail

• battery, metal nail, wire

• glass rod, wire, battery

• glass rod, string, battery

Multiple Choice

• It will distribute itself evenly over the surface of the sphere, because like charges repel and the sphere is a conductor.

• It will remain at the point of contact between the rod and the sphere, because resistance in the metal prevents the charges from easily moving.

• It will quickly spread to the air around the sphere, because it will seek to occupy as large a volume of neutral matter as possible.

• It will slowly drift to the bottom of the sphere, because the charges rapidly attach to individual atoms, making them slightly heavier than surrounding atoms.

Multiple Choice

What is the transfer of energy in a generator?

• electrical to mechanical

• chemical to radiant

• electrical to chemical

• mechanical to electrical

Multiple Choice

A student wraps insulated copper wire 12 times around a nail, and connects the ends to a fresh 9-volt battery. The student finds that the nail can now be used to lift small iron weights. The student disconnects the circuit and wraps a longer copper wire 30 times around another nail of the same type. The student then connects the wire to a fresh 9-volt battery. What should the student observe when attempting to use the new nail to lift small iron weights?

• The nail will be able to lift heavier weights, because the greater number of turns of the wire yields a more powerful magnetic field.

• The nail will be able to lift heavier weights, because the greater mass of conductive matter in the system will balance a greater mass of iron in the weights.

• The nail will only be able to lift the same amount of weight, because the magnetic force of the system depends on the current from the battery, which has not changed.

• The nail will only be able to lift the same amount of weight, because the physical properties of the nail determine magnetic force, and nails of the same type were used in both trials.

Multiple Choice

Seamus made an electromagnet from an iron nail, a piece of copper wire with three coils spread out across the nail, and a AAA-sized battery. His magnet attracts only one paper clip, and he wants to boost the power of his magnet to attract at least four paper clips. What two things can Seamus do to accomplish his goal?

• Seamus can add batteries to decrease the voltage, and he can decrease the space between the wire coils.

• Seamus can add batteries to increase the voltage, and he can increase the space between the wire coils.

• Seamus can add batteries to increase the voltage, and he can decrease the space between the wire coils.

• Seamus can add batteries to decrease the voltage, and he can increase the space between the wire coils.

Multiple Choice

Brielle tests the difference in the magnetic force of two electromagnets with different numbers of wire turns around the iron nails. She observes that the electromagnet with ten wire turns attracts more paper clips than the electromagnet with seven wire turns. What is her conclusion?

• Magnetic force increases with an increase in the number of wire turns around an iron nail.

• Magnetic force decreases with an increase in the number of wire turns around an iron nail.

• Magnetic force increases with a decrease in the number of wire turns around an iron nail.

• Magnetic force is not affected by a change in the number of wire turns around an iron nail.

Multiple Choice

What results from a wire carrying a current?

• an electric field

• a magnetic field

• beams of white light

• the dispersion of photons

Multiple Choice

Two new planets are discovered, planet X and planet Y. The planets have identical volumes, but the mass of planet X is two times greater than the mass of planet Y. If two identical space ships land on each planet, which of the following will be true?

• The mass of the space ship on planet Y will be greater than the mass of the space ship on planet X.

• The weight of the space ship on planet Y will be greater than the weight of the space ship on planet X.

• The mass of the space ship on planet X will be greater than the mass of the space ship on planet Y.

• The weight of the space ship on planet X will be greater than the weight of the space ship on planet Y.

Multiple Choice

Harper touches a negatively charged plastic rod to a rubber ball. How are the negative charges distributed on the rubber ball?

• They move to the bottom surface of the ball.

• They are evenly distributed on the inside of the ball.

• They are evenly distributed on the surface of the ball.

• They stay on the surface where the rod touches the ball.

Multiple Choice

Ahmad made a very simple electromagnet out of a nail, copper wire, and a AAA-sized battery. His magnet was able to lift one paper clip from 2 centimeters away. Which of the following is NOT a way Ahmad can improve the strength of his electromagnet?

• He can reverse the orientation of his battery

• He can use a thicker piece of the copper wire.

• He can increase the size and voltage of his battery.

• He can use longer wire for more coils around the nail.

Multiple Choice

Jazelle has five different-sized magnets. She puts each magnet far away from a paper clip and slowly moves it closer until it attracts the paper clip. She records the distance between the magnet and the paper clip when it attracts. What is Jazelle's experiment designed to test?

• how the size of a magnet affects the strength of its magnetic pull on objects

• how the type of paper clip affects the way in which it reacts to the force of a magnet

• how the distance away from a magnet affects a paper clip's chances of being attracted

• how the magnetic force of a magnet affects the movement of an object

Multiple Choice

Kayla has two magnets. She would like to know how much magnetic energy is stored in each one. What would be the best way for her to determine which magnet has the most magnetic energy?

• Attach wires to the ends of each magnet and measure the currents going through the wires.

• Put each magnet into a beaker of water to see how much water it displaces.

• Measure how close each 0magnet can get to a metal object before picking it up.

• Record the mass of each magnet by measuring it on a balance scale

Multiple Choice

Which type of electromagnetic core will create the strongest magnetic field?

• another magnet

• a wooden pencil

• an iron nail

• a glass rod