1.
The relationship between electricity and magnetism is known as what?
Correct Answer
B. Electromagnetism
Explanation
The relationship between electricity and magnetism is known as electromagnetism. This term refers to the phenomenon where an electric current generates a magnetic field and a changing magnetic field induces an electric current. Electromagnetism is a fundamental concept in physics and is the basis for many practical applications, such as electric motors, generators, and transformers.
2.
How many poles does a magnet have?
Correct Answer
B. 2 poles
Explanation
A magnet has two poles, a north pole and a south pole. These poles are regions where the magnetic field is the strongest. Opposite poles attract each other, while like poles repel each other. The concept of magnetic poles is a fundamental characteristic of magnets and is independent of the shape of the magnet. Therefore, the correct answer is 2 poles.
3.
The Clothes in a dryer acquire static cling due to what?
Correct Answer
D. Friction
Explanation
When clothes rub against each other in a dryer, friction is created. This friction causes the transfer of electrons between the clothes, resulting in a buildup of static electricity. This static electricity causes the clothes to stick together or cling to the sides of the dryer.
4.
The loss of static electricity in the object as electric charges move off an object is called what?
Correct Answer
D. Static discharge
Explanation
Static discharge refers to the loss of static electricity in an object as electric charges move off the object. This occurs when there is a buildup of static electricity on an object, and the excess charges are released through a sudden flow of electric current. Static discharge can be observed in various situations, such as when a person gets shocked after walking on a carpet and then touching a metal object. It is an important phenomenon to understand in order to prevent potential hazards associated with static electricity buildup.
5.
What is the name of the component that produces power in an electromagnetic generator?
Correct Answer
B. Armature
Explanation
The armature is the component in an electromagnetic generator that produces power. It is a rotating coil of wire that is connected to the electrical load. As the armature rotates within the magnetic field created by the field winding, an electromotive force is induced in the armature coil, generating power. The armature is a crucial part of the generator as it converts mechanical energy into electrical energy.
6.
What is the relationship between the magnetic reluctance of a material with respect to its cross-sectional area?
Correct Answer
A. It Decreases with increase in cross sectional area of material
Explanation
The relationship between the magnetic reluctance of a material and its cross-sectional area is that it decreases with an increase in the cross-sectional area of the material. This means that as the cross-sectional area of the material increases, it becomes easier for magnetic flux to pass through it, resulting in a decrease in magnetic reluctance.
7.
Which of the following magnet can be easily turned on and off?
Correct Answer
C. An electromagnet
Explanation
An electromagnet can be easily turned on and off because it is created by passing an electric current through a coil of wire, which produces a magnetic field. By controlling the flow of electric current, the electromagnet's magnetic field can be switched on or off, allowing for easy manipulation and control. In contrast, a refrigerator magnet is a permanent magnet and cannot be easily turned on or off. Magnetite is also a natural permanent magnet, while a ferromagnet is a material that can become permanently magnetized but cannot be easily switched on or off like an electromagnet.
8.
What happens when the South poles of two magnets are brought close to each other?
Correct Answer
B. They repel each other
Explanation
When the South poles of two magnets are brought close to each other, they repel each other. This is because like poles of magnets repel each other due to the magnetic force between them.
9.
Which of the following will make an electromagnet weaker?
Correct Answer
D. Removal of one of the nails from the coils
Explanation
Electromagnets work by wrapping coils of wire around a magnetic core (such as a nail) and passing an electric current through the wire. The magnetic field generated by the electromagnet is directly related to the number of coils wrapped around the core and the amount of current passing through the wire.
Therefore, by removing one of the nails from the coils, you are reducing the number of coils in the electromagnet, which decreases the strength of the magnetic field produced.
10.
Who discovered electromagnetism?
Correct Answer
B. Michael Faraday
Explanation
Michael Faraday is credited with discovering electromagnetism. He conducted numerous experiments and made significant contributions to the understanding of electromagnetism. Faraday's experiments with magnets and electric currents led him to discover the principle of electromagnetic induction, which laid the foundation for the development of electric generators and transformers. His work revolutionized the field of electromagnetism and paved the way for future advancements in technology.