Electricity/Magnetism DFA Review

An object can become electrically charged if it gains or loses which particles?

• volts

• neutrons

• protons

• electrons

A charged object (A) comes in to contact with an uncharged object (B). In the process, object A loses electrons and object B gains electrons. Which of the following is true?

• Object B lost protons

• Object B has no charge

• Object B now has a positive charge

• Object B now has a negative charge

What will happen to a positive charged object and a negative charged object when they are placed near each other?

• the objects will remain still

• the charges transferred to another object

• the charges switched from negative to positive

• the charges broke apart into smaller positive and negative particles

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Which of the following best describes a magnetic field?

• a measure of the length of the magnet

• an invisible region that surrounds the north pole of a magnet

• an invisible region that surrounds the north pole of a magnet

• a region around a magnet in which you can measure magnetic forces

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How does Earth’s magnetic field compare with that of a bar magnet?

• their magnetic fields increase with size

• the attractive force of the magnetic fields is greatest at the poles

• the attractive force of their magnetic fields is greatest at the center

• electric current causes them to lose magnetism

The students continued their experiments on force fields, this time investigating magnetism. One group student set up the demonstration you see here. “Oh wow!” Sarah exclaimed. “It’s magic!” Is it magic? Which statement best explains how the center magnet is able to hover between two other magnets?

• the magnets are stacked so that like poles are facing one another

• the opposite poles of each magnet are facing each other so they repel

• the middle magnet is repelling the top magnet while attracting the bottom

• the middle magnet is attracted to the top magnet but pulled down by gravity

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Jason places a bar magnet on a flat surface and covers it with a sheet of paper. Then he evenly sprinkles a layer of iron filings on top of the paper. Which of the following diagrams indicates the most likely arrangement of the filings on the paper?

• Figure A

• Figure B

• Figure C

• Figure D

Candice learns that all magnets have two magnetic poles. Which of the following observations would best support this statement?

• When a bar magnet is cut in half, each half has a north pole and a south pole.

• the north pole of a compass needle is attracted to the south pole of a bar magnet

• when an electric current flows through a wire, a magnetic field forms around the wire

• the strength of a horseshoe magnet’s magnetic field decreases as the magnet is pulled away from another object

Using the image below, where is the magnetic field of this magnet the strongest?

• Position A

• Position B

• Position C

• Position D

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Objects can be charged in many ways. In the image below, a student is rubbing a balloon on her head.

What method is this student using to charge the balloon?

• friction

• repulsion

• induction

• conduction