1.
Bar magnets have two poles. What are they?
Correct Answer
A. North and south
Explanation
Bar magnets have two poles, which are known as the north and south poles. These poles are opposite in nature and exhibit magnetic properties. The north pole of a magnet is attracted to the south pole of another magnet, while similar poles repel each other. This phenomenon is the basis for many applications of magnets, such as in compasses and magnetic storage devices.
2.
What could you detect using a magnet and iron filings?
Correct Answer
C. Magnetic field
Explanation
By using a magnet and iron filings, you can detect a magnetic field. When the magnet is brought close to the iron filings, they align themselves along the magnetic field lines, revealing the presence and direction of the magnetic field. This phenomenon occurs due to the magnetic properties of iron filings, which are attracted to the magnet and align themselves accordingly. Therefore, the correct answer is magnetic field.
3.
Where is the pushing a pulling force of a bar magnet strongest?
Correct Answer
A. At the ends of a magnet
Explanation
The pushing and pulling force of a bar magnet is strongest at the ends of the magnet. This is because the magnetic field lines are most concentrated at the poles of the magnet. The magnetic field lines originate from one pole, called the north pole, and terminate at the other pole, called the south pole. The density of these field lines is highest at the poles, resulting in a stronger force. In contrast, the force is weaker in the middle of the magnet because the magnetic field lines are more spread out.
4.
Magnetism is a type of...
Correct Answer
B. Force
Explanation
Magnetism is a type of force. It is the force that attracts or repels certain materials, such as iron or nickel, and is caused by the motion of electric charges. The force of magnetism is responsible for various phenomena, such as the attraction between magnets and the alignment of compass needles. Unlike electricity, which is the flow of charged particles, magnetism is a force that acts on charged particles and can exist even without the presence of electric current. Therefore, force is the correct answer to describe magnetism.
5.
If magnet A can hold 3 paperclips and magnet B can hold 5 paperclips, which magnet is stronger?
Correct Answer
B. Magnet B
Explanation
Magnet B is stronger because it can hold more paperclips than magnet A.
6.
Two magnetic poles that are the same _____ each other
Correct Answer
B. Repel
Explanation
When two magnetic poles are the same, they repel each other. This is because like poles of magnets have the same magnetic orientation, causing the magnetic field lines to push against each other. As a result, the two magnets will exert a force that pushes them apart, leading to repulsion.
7.
What does repel mean?
Correct Answer
B. Magnets move away from each other
Explanation
The term "repel" refers to the action of magnets moving away from each other. When two magnets are brought close to each other, their like poles (north and north, or south and south) will repel each other, causing the magnets to move apart. This phenomenon is due to the magnetic field lines of the magnets interacting and creating a force that pushes them away from each other.
8.
Which object would not attract a magnet?
Correct Answer
C. Water
Explanation
Water does not attract a magnet because it is a non-magnetic substance. Unlike metals such as scissors, nail, and screw, water does not contain magnetic properties. It does not have a magnetic field or align its atoms in a way that would attract or be influenced by a magnet. Therefore, a magnet would not be attracted to water.
9.
Which element is responsible for the magnetic force?
Correct Answer
A. Iron
Explanation
Iron is responsible for the magnetic force because it is a ferromagnetic material. Ferromagnetic materials, like iron, have a high susceptibility to magnetization and can retain their magnetic properties even after an external magnetic field is removed. This means that iron can be easily magnetized and can create a magnetic field, making it the element most commonly associated with magnetic forces.
10.
Does distance strengthen or weaken a magnets ability to attract?
Correct Answer
B. Weaken
Explanation
Distance weakens a magnet's ability to attract. As the distance between the magnet and the object increases, the magnetic force between them decreases. This is because the magnetic field produced by the magnet becomes less concentrated and spreads out over a larger area as the distance increases. Therefore, the attraction between the magnet and the object becomes weaker.
11.
Naturally occuring magnets in nature are called -
Correct Answer
C. Lodestones
Explanation
Naturally occurring magnets in nature are called lodestones. Lodestones are a type of magnetic rock that can attract iron objects. They are formed when certain minerals in rocks align themselves with the Earth's magnetic field during the rock's formation. Lodestones have been used by humans for centuries for various purposes, such as navigation and creating compasses.
12.
When magnets are broken into small bits ,the bits themselves can become small magnets.
Correct Answer
A. True
Explanation
When magnets are broken into small bits, the bits themselves can become small magnets. This is because magnets are made up of tiny magnetic domains, and breaking a magnet into smaller pieces allows these domains to align and create smaller magnets. Each small bit retains its magnetic properties and can attract or repel other magnetic materials. Therefore, it is true that when magnets are broken into small bits, the bits themselves can become small magnets.
13.
Which of these is NOT used to create a simple electromagnet?
Correct Answer
B. Light bulb
Explanation
A light bulb is not used to create a simple electromagnet. An electromagnet is typically created by passing an electric current through a coil of copper wire wrapped around an iron core. The electric current generates a magnetic field, turning the coil into a magnet. However, a light bulb does not have the necessary components or design to generate a magnetic field and cannot be used to create an electromagnet.
14.
The negatively charged particles within atoms are
Correct Answer
A. Electrons
Explanation
The negatively charged particles within atoms are electrons. Electrons are subatomic particles that orbit around the nucleus of an atom. They have a negative charge and are responsible for the electrical conductivity and chemical reactions of atoms. Protons, on the other hand, are positively charged particles found in the nucleus of an atom. The nucleus is the central part of an atom that contains protons and neutrons. Orbits, in this context, refer to the path or trajectory followed by electrons around the nucleus.
15.
An example of a ferromagnetic material is
Correct Answer
A. Iron
Explanation
Iron is an example of a ferromagnetic material because it has strong magnetic properties. When placed in a magnetic field, iron can become magnetized and retain its magnetism even after the field is removed. This is due to the alignment of its atomic dipoles, which allows iron to exhibit a strong attraction to magnets. Plastic, copper, and wood are non-magnetic materials, so they are not examples of ferromagnetic materials.
16.
What makes a compass work
Correct Answer
D. It spins freely
Explanation
A compass works because it spins freely. This allows the compass needle, which is magnetized, to align itself with the Earth's magnetic field. The Earth acts like a giant magnet with its magnetic north and south poles, and the compass needle aligns itself with these poles, indicating the direction of north. The spinning motion of the compass needle allows it to move freely and align itself with the Earth's magnetic field.
17.
A stream of electrically charged particles flowing from the sun is called
Correct Answer
C. Solar wind
Explanation
The correct answer is solar wind. The stream of electrically charged particles flowing from the sun is referred to as solar wind. These particles, mainly electrons and protons, are emitted by the sun's outer atmosphere and travel at high speeds throughout the solar system. The solar wind plays a crucial role in shaping the magnetosphere and interacting with planetary atmospheres.
18.
The region of the earth's magnetic field shaped by the solar wind is called the
Correct Answer
B. MagnetospHere
Explanation
The region of the earth's magnetic field shaped by the solar wind is called the magnetosphere. The solar wind, which is a stream of charged particles emitted by the Sun, interacts with the earth's magnetic field and creates a protective bubble around the planet. This magnetosphere deflects most of the solar wind, preventing it from directly reaching the earth's surface. The interaction between the solar wind and the earth's magnetosphere also produces phenomena such as the auroras, which are colorful lights seen in the polar regions.
19.
In an atom the electrons and protons are located in the nucleus.
Correct Answer
B. False
Explanation
The given statement is false. In an atom, the electrons are located outside the nucleus in energy levels or shells, while the protons are located inside the nucleus. The nucleus contains the protons and neutrons, while the electrons orbit around the nucleus.
20.
How can you make a metal into a temporary magnet?
Correct Answer
B. Rub a permanent magnet across the magnetic material in the same direction
Explanation
Rubbing a permanent magnet across the magnetic material in the same direction can create a temporary magnet because it aligns the magnetic domains within the material in the same direction. This alignment causes the material to exhibit magnetic properties temporarily, similar to a magnet. However, this magnetism will fade over time as the domains gradually return to their original random orientation.
21.
What can you say about the domains of a permanent magnet?
Correct Answer
A. They are aligned in the same direction
Explanation
The correct answer is that the domains of a permanent magnet are aligned in the same direction. This means that the magnetic moments of the atoms within the magnet are all pointing in the same direction, resulting in a strong magnetic field. When the domains are aligned, the magnet exhibits its magnetic properties, such as attracting or repelling other magnets or magnetic materials. This alignment is achieved during the manufacturing process of the magnet, where an external magnetic field is applied to align the domains in a specific direction.
22.
What does a generator do?
Correct Answer
B. It converts mechanical energy into electrical energy
Explanation
A generator is a device that converts mechanical energy into electrical energy. It does this by using a mechanical force, such as a turbine or engine, to spin a magnet inside a coil of wire. This spinning magnet creates a changing magnetic field, which induces an electric current in the wire. The generated electrical energy can then be used to power various devices and systems.
23.
What does a motor do?
Correct Answer
A. It converts electrical energy to mechanical energy
Explanation
A motor is a device that converts electrical energy into mechanical energy. It does this by utilizing the electromagnetic principle, where the interaction between electric currents and magnetic fields generates a force that causes the motor to rotate. This rotation can then be used to perform various mechanical tasks, such as powering machinery or generating movement.
24.
How do we know that the earth has magnetic field?
Correct Answer
B. The rocks on the ocean floor leave a record of magnetic field lines
Explanation
The correct answer is "the rocks on the ocean floor leave a record of magnetic field lines." This is because when molten lava solidifies into rocks, it preserves the orientation of the Earth's magnetic field at the time. By studying the magnetic properties of these rocks, scientists can determine the history and strength of the Earth's magnetic field over time. This evidence confirms the existence of the Earth's magnetic field.
25.
Maglev trains use magnets to elevate trains so that they never touch the tracks. The poles of the magnets on the trains facing the poles of the magnets on the tracks must be...
Correct Answer
B. The same, so they repel each other
Explanation
The correct answer is "the same, so they repel each other." This is because like poles of magnets repel each other. In the case of maglev trains, the magnets on the trains and the magnets on the tracks have the same poles facing each other, causing a repelling force that allows the train to levitate above the tracks.
26.
In a science lab, Claudio rubs the north pole of a bar magnet against a wooden coffee stirrer, an iron nail, and a plastic spoon. After rubbing each item for two minutes, Caludio tries to pick up one steel paper clip using each object. The independent variable tested in this experiment is...
Correct Answer
B. The magnetic properties of the selected materials
Explanation
The independent variable tested in this experiment is the magnetic properties of the selected materials. The experiment is designed to investigate how different materials respond to the magnetic field of the bar magnet. By rubbing the north pole of the magnet against the wooden coffee stirrer, iron nail, and plastic spoon, Claudio is testing the magnetic properties of each material. The outcome of the experiment, whether or not the steel paper clip can be picked up, will depend on the magnetic properties of the selected materials.