Unit 2 Practice Benchmark

Anna walked across her living room floor and then reached for the door knob to the closet and felt a shock. Which of the following would provide evidence for why she got shocked?

• Protons build up on a person’s body.

• Protons transfer from the doorknob to a person’s body.

• Electrons transfer from a person’s body to the doorknob.

• Electrons build up on the doorknob.

Which two of the following describes how a positive test charge moves in the electric field created by a positive and a negative charge?

• It is repelled by the negative charge.

• It remains stationary.

• It is attracted to the positive charge.

• It moves away from the positive charge.

• It moves toward the negative charge.

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5

What happens to the strength of the electric field at the midpoint between two opposite charges?

• The strength of the electrical field at the midpoint between the two opposite charges is the same as the strength of the electrical field near each charge, because the electric field vectors subtract their strength at the midpoint.

• The strength of the electrical field at the midpoint between the two opposite charges is stronger than the strength of the electrical field near each charge, because the electric field vectors subtract their strength at the midpoint.

• The strength of the electrical field at the midpoint between the two opposite charges is stronger than the strength of the electrical field near each charge, because the electric field vectors add their strength at the midpoint.

• The strength of the electrical field at the midpoint between the two opposite charges is weaker than the strength of the electrical field near each charge, because the electric field vectors add their strength at the midpoint.

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5

Electric Force is the force that exists between all charged particles. Which of the following statements about the electric force between two charged objects is true?

• As the distance between the charges decreases, the strength of the electric force gets weaker.

• The strength of the electric force is not affected by how far apart the charges are.

• As the charge gets larger, the strength of the electric force gets stronger.

• As the charges get larger, the strength of the electric force gets weaker.

Tags

NGSS.MS-PS2-3

Two plastic balls with the charges of +1.0 and −2.0 are released in an electric field. Which of the following statements would describe what would happen when these two charges interact?

• The balls move apart because they exert equal repulsive forces on each other.

• The negatively charged ball does not move, but the positively charged ball starts to move toward the negatively charged ball because of an attractive force.

• The balls start moving towards each other because they have an attractive force due to their opposite charges.

• The plastic balls would remain where they are.

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5

Photocopiers are devices that use electrostatic forces to create images on paper. Electrostatic forces play a critical role in the attraction and repulsion of charged particles enabling precise control over the movement of toner. Choose the best response to explain why electric forces are crucial in the operation of photocopiers.

• They create heat for the copier.

• They produce sound to influence the particles.

• They attract and repel toner particles.

• They generate light for the copier screen.

Tags

NGSS.MS-PS2-3

Appliances use heating elements to generate heat and cook food. In appliances like toasters and ovens, heating elements are strategically placed to direct heat efficiently. Heating elements are made from materials that do not conduct electricity readily, such as nichrome. These materials are selected because they effectively convert electrical energy into heat. What principle do heating elements use to generate heat?

• Chemical reaction

• Thermal conduction

• Electrical resistance

• Magnetic induction

Tags

NGSS.MS-PS3-3

What causes the compass needle to point toward Earth’s magnetic North Pole?

• The rotation of the Earth on its axis

• The interaction between true geographic north and magnetic north

• The interaction between the needle and Earth’s magnetic field

• The gravitational pull of the Earth by the sun

Kai and Hannah are conducting an experiment to understand different forces. Which data would be useful for distinguishing between electric and magnetic forces?

• Counting the number of coils in a wire for magnetic strength

• Recording light intensity changes through materials

• Observing how charges interact versus how magnetic poles interact

• Measuring temperature changes in different sized wires with current

Tags

NGSS.MS-PS2-3

How does increasing the thickness of the wire affect the electromagnet’s strength at a constant voltage?

• There was no change.

• The wire thickness was irrelevant.

• The number of paper clips picked up increased.

• The number of paper clips picked up decreased.