4.1 Flashcards
Q: What are the ends of a magnet called?
A: The ends of a magnet are called poles.
Q: How many poles does a magnet have?
A: Magnets have two poles: a north pole and a south pole.
Q: What does the Law of Magnetism state?
A: The Law of Magnetism states that two like poles repel each other, while two unlike poles attract each other.
Q: What happens when two magnets are held close together?
A: When two magnets are held close together, there will be an attractive or repulsive force between them depending on how they are arranged.
Q: What is an example of a non-contact force related to magnets?
A: The attraction or repulsion between two magnetic poles is an example of a non-contact force
Q: How can attraction and repulsion be shown by magnets?
A: Attraction and repulsion can be shown by the magnetic field patterns around bar magnets.
Q: What do the magnetic field lines look like for attracting and repelling bar magnets?
A: The magnetic field lines for attracting and repelling bar magnets form distinct patterns around the magnets.
Q: Which metals in the Periodic Table are magnetic?
A: The metals in the Periodic Table that are magnetic include iron, cobalt, and nickel.
Q: Why is steel considered magnetic?
A: Steel, being an alloy containing iron, is also magnetic.
Q: What happens when magnetic materials are brought close to a magnet?
A: Magnetic materials will always be attracted to the magnet, regardless of which pole is held close to it.
Q: How can you test whether a material is a magnet?
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.
Q: What are the two types of magnets?
A: The two types of magnets are permanent magnets and induced magnets.
Q: What are permanent magnets made of?
A: Permanent magnets are made out of permanent magnetic materials, such as steel.
Q: What happens when a magnetic material is placed in a magnetic field?
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.
Q: What occurs when magnetism is induced on a material?
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
Q: How are induced magnets different from permanent magnets?
A: Induced magnets are temporary magnets, whereas permanent magnets retain their magnetism indefinitely.
Q: Why do magnetic materials always get attracted to a permanent magnet?
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.
Q: What is a magnetic field?
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.
Q: How are magnetic field lines used to represent a magnetic field?
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.
Q: What are the characteristics of a strong magnetic field?
A: A strong magnetic field is indicated by magnetic field lines that are close together.
Q: What rules must be followed when drawing magnetic field lines?
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.
Q: Where is the magnetic field strongest around a bar magnet?
A: The magnetic field is strongest at the poles of the magnet, where the field lines are closest together.
Q: What is a uniform magnetic field?
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
Q: How can the shape and direction of a magnetic field be investigated?
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.
Q: Describe the process of investigating magnetic field lines using plotting compasses.
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.
Q: What does a magnetic compass indicate about the Earth’s magnetic field?
A: A magnetic compass will always point north on Earth, indicating the presence of the Earth’s magnetic field.
What does the behavior of a magnetic compass suggest about the Earth’s core?
A: The behavior of a magnetic compass suggests that the core of the Earth is magnetic and generates its own magnetic field.
How is the Earth’s magnetic field similar to that of a bar magnet?
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.
Q: Why does the north arrow on a magnetic compass point towards the geographic North Pole?
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.
Q: What happens when the north pole of a magnetic compass approaches the Earth’s magnetic south pole?
A: When the north pole of a magnetic compass approaches the Earth’s magnetic south pole, it is attracted to it.
Q: Why is the north pole of a magnetic compass repelled from the Earth’s magnetic north pole?
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.
Q: What happens when a current flows through a conducting wire?
A: When a current flows through a conducting wire, a magnetic field is produced around the wire.
Q: How can the shape and direction of the magnetic field around a wire be investigated?
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.
Q: What is the right-hand thumb rule used for?
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.
Q: What factors affect the strength of the magnetic field around a wire?
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.
Q: How does coiling a wire affect the magnetic field?
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.
Q: How can the polarity of each end of a solenoid be determined?
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
Q: How can the strength of the magnetic field around a solenoid be increased?
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.
