4.1

Question 1

Q: What are the ends of a magnet called?

Answer 1

A: The ends of a magnet are called poles.

Question 2

Q: How many poles does a magnet have?

Answer 2

A: Magnets have two poles: a north pole and a south pole.

Question 3

Q: What does the Law of Magnetism state?

Answer 3

A: The Law of Magnetism states that two like poles repel each other, while two unlike poles attract each other.

Question 4

Q: What happens when two magnets are held close together?

Answer 4

A: When two magnets are held close together, there will be an attractive or repulsive force between them depending on how they are arranged.

Question 5

Q: What is an example of a non-contact force related to magnets?

Answer 5

A: The attraction or repulsion between two magnetic poles is an example of a non-contact force

Question 6

Q: How can attraction and repulsion be shown by magnets?

Answer 6

A: Attraction and repulsion can be shown by the magnetic field patterns around bar magnets.

Question 7

Q: What do the magnetic field lines look like for attracting and repelling bar magnets?

Answer 7

A: The magnetic field lines for attracting and repelling bar magnets form distinct patterns around the magnets.

Question 8

Q: Which metals in the Periodic Table are magnetic?

Answer 8

A: The metals in the Periodic Table that are magnetic include iron, cobalt, and nickel.

Question 9

Q: Why is steel considered magnetic?

Answer 9

A: Steel, being an alloy containing iron, is also magnetic.

Question 10

Q: What happens when magnetic materials are brought close to a magnet?

Answer 10

A: Magnetic materials will always be attracted to the magnet, regardless of which pole is held close to it.

Question 11

Q: How can you test whether a material is a magnet?

Answer 11

A: To test whether a material is a magnet, it should be brought close to a known magnet. If it can be repelled by the known magnet, then the material itself is a magnet. If it can only be attracted and not repelled, then it is a magnetic material.

Question 12

Q: What are the two types of magnets?

Answer 12

A: The two types of magnets are permanent magnets and induced magnets.

Question 13

Q: What are permanent magnets made of?

Answer 13

A: Permanent magnets are made out of permanent magnetic materials, such as steel.

Question 14

Q: What happens when a magnetic material is placed in a magnetic field?

Answer 14

A: When a magnetic material is placed in a magnetic field, it can temporarily be turned into a magnet. This phenomenon is called induced magnetism.

Question 15

Q: What occurs when magnetism is induced on a material?

Answer 15

A: When magnetism is induced on a material, one end of the material will become a north pole, and the other end will become a south pole

Question 16

Q: How are induced magnets different from permanent magnets?

Answer 16

A: Induced magnets are temporary magnets, whereas permanent magnets retain their magnetism indefinitely.

Question 17

Q: Why do magnetic materials always get attracted to a permanent magnet?

Answer 17

A: Magnetic materials always get attracted to a permanent magnet because the end of the material closest to the magnet will have the opposite pole to the magnet’s pole closest to the material.

Question 18

Q: What is a magnetic field?

Answer 18

A: A magnetic field is the region around a magnet where a force acts on another magnet or on a magnetic material such as iron, steel, cobalt, and nickel.

Question 19

Q: How are magnetic field lines used to represent a magnetic field?

Answer 19

A: Magnetic field lines are used to represent the strength and direction of a magnetic field. The direction is shown using arrows, and the strength is indicated by the spacing between the lines.

Question 20

Q: What are the characteristics of a strong magnetic field?

Answer 20

A: A strong magnetic field is indicated by magnetic field lines that are close together.

Question 21

Q: What rules must be followed when drawing magnetic field lines?

Answer 21

A: Magnetic field lines should always go from north to south, indicated by an arrow midway along the line. They must never touch or cross other field lines.

Question 22

Q: Where is the magnetic field strongest around a bar magnet?

Answer 22

A: The magnetic field is strongest at the poles of the magnet, where the field lines are closest together.

Question 23

Q: What is a uniform magnetic field?

Answer 23

A: A uniform magnetic field is one that has the same strength and direction at all points. This means there is equal spacing between magnetic field lines, and they all have arrows going from the north pole to the south pole

Question 24

Q: How can the shape and direction of a magnetic field be investigated?

Answer 24

A: The shape and direction of a magnetic field can be investigated using plotting compasses. These compasses are like small bar magnets with a north and south pole.

Question 25

Q: Describe the process of investigating magnetic field lines using plotting compasses.

Answer 25

A: 1. Place the magnet on top of a piece of paper and draw a dot at one end.

Place a plotting compass next to the dot so that one end of the compass needle points away from the dot, and draw a new dot at the other side of the compass needle.
Repeat this process, moving the compass away from each new dot, until there is a chain of dots from one end of the magnet to the other.
Remove the compass and connect the dots with a smooth curve to represent the magnetic field line.
Repeat this process several times to create several magnetic field lines around the magnet.

Question 26

Q: What does a magnetic compass indicate about the Earth’s magnetic field?

Answer 26

A: A magnetic compass will always point north on Earth, indicating the presence of the Earth’s magnetic field.

Question 27

What does the behavior of a magnetic compass suggest about the Earth’s core?

Answer 27

A: The behavior of a magnetic compass suggests that the core of the Earth is magnetic and generates its own magnetic field.

Question 28

How is the Earth’s magnetic field similar to that of a bar magnet?

Answer 28

A: The Earth’s magnetic field is similar to that of a bar magnet in that it has a north pole and a south pole, and the magnetic field lines resemble those around a bar magnet.

Question 29

Q: Why does the north arrow on a magnetic compass point towards the geographic North Pole?

Answer 29

A: The north arrow on a magnetic compass points towards the geographic North Pole because the geographic North Pole is a magnetic south pole, and the magnetic field lines point into the pole.

Question 30

Q: What happens when the north pole of a magnetic compass approaches the Earth’s magnetic south pole?

Answer 30

A: When the north pole of a magnetic compass approaches the Earth’s magnetic south pole, it is attracted to it.

Question 31

Q: Why is the north pole of a magnetic compass repelled from the Earth’s magnetic north pole?

Answer 31

A: The north pole of a magnetic compass is repelled from the Earth’s magnetic north pole because the geographic South Pole, which is a magnetic north pole, has magnetic field lines pointing out of the pole.

Question 32

Q: What happens when a current flows through a conducting wire?

Answer 32

A: When a current flows through a conducting wire, a magnetic field is produced around the wire.

Question 33

Q: How can the shape and direction of the magnetic field around a wire be investigated?

Answer 33

A: The shape and direction of the magnetic field around a wire can be investigated using plotting compasses. The field is typically represented by concentric circles around the wire.

Question 34

Q: What is the right-hand thumb rule used for?

Answer 34

A: The right-hand thumb rule is used to determine the direction of the magnetic field around a current-carrying wire. It aligns the thumb in the direction of the current, and the fingers curl in the direction of the magnetic field.

Question 35

Q: What factors affect the strength of the magnetic field around a wire?

Answer 35

A: The strength of the magnetic field around a wire depends on the size of the current and the distance from the wire. Larger currents produce stronger magnetic fields, and the field strength decreases with increasing distance from the wire.

Question 36

Q: How does coiling a wire affect the magnetic field?

Answer 36

A: Coiling a wire into a solenoid increases the strength of the magnetic field. The magnetic field around a solenoid is similar to that of a bar magnet, and the field inside the solenoid is strong and uniform.

Question 37

Q: How can the polarity of each end of a solenoid be determined?

Answer 37

A: The polarity of each end of a solenoid can be determined by viewing it from the end. If the current flows clockwise around the solenoid, one end behaves like the south pole; if the current flows counterclockwise, that end behaves like the north pole

Question 38

Q: How can the strength of the magnetic field around a solenoid be increased?

Answer 38

A: The strength of the magnetic field around a solenoid can be increased by increasing the size of the current, increasing the number of coils, or adding an iron core through the center of the coils, which becomes an induced magnet when current flows through the coils.