Long Questions: Fun with Magnets | NCERT Summary: UPSC PDF Download

Q1: What care should be taken while handling magnets?
Ans: Magnets should be handled with caution to avoid losing their magnetic properties.
The following are some precautions to take when handling the magnet:

• Magnets should never be fired, hammered, or thrown from a great height.
• Magnets should be stored in pairs, with opposite poles facing each other.
• A piece of wood must be used to separate the magnets, with a piece of soft iron placed across their ends.
• A piece of iron should be kept across the poles of a horse-shoe magnet.
• We should keep magnets away from televisions, laptops, CDs, cassette tapes, mobile phones, and music systems.

Q2: Explain the concept of a magnet and its properties. Describe the two poles of a magnet and their behavior when brought close to each other. Provide examples of natural and artificial magnets.
Ans:

• A magnet is an object that attracts certain materials like iron, cobalt, and nickel. It has two ends called poles: the North Pole (N) and the South Pole (S). The properties of a magnet include its ability to attract iron and the ability to repel or attract another magnet depending on their poles.
• Pole Behavior: Like poles (N-N or S-S) repel each other, while unlike poles (N-S) attract each other.
• Examples: Natural magnets include lodestone, a type of rock with magnetic properties. Artificial magnets are created by magnetizing materials like iron or steel.

Q3: Describe the concept of magnetic materials and non-magnetic materials. Provide examples of materials that fall under each category.
Ans:

• Magnetic Materials: These materials are attracted to magnets. Iron, cobalt, and nickel are examples of magnetic materials. They can become magnets when brought into contact with a strong magnet.
• Non-Magnetic Materials: These materials are not attracted to magnets. Wood, plastic, glass, and rubber are examples of non-magnetic materials.
• Example: A paperclip (made of iron) is attracted to a magnet, while a wooden pencil is not attracted.

Q4: Explain the concept of the Earth's magnetic field. Describe the behavior of a freely suspended magnet, its North and South Poles, and how it aligns with the Earth's magnetic field.
Ans:

• The Earth's magnetic field is the region around the Earth where its magnetic influence is felt. It is similar to a bar magnet, with a North Magnetic Pole and a South Magnetic Pole.
• Magnet Behavior: A freely suspended magnet aligns itself in a north-south direction because of the Earth's magnetic field. The North Pole of a freely suspended magnet points towards the Earth's geographic North Pole, which is actually the magnetic South Pole.
• Example: If you hang a freely suspended bar magnet, one end will point towards the geographic North Pole (which is the magnetic South Pole) and the other end towards the geographic South Pole (which is the magnetic North Pole).

Q5: Explain the concept of the attraction and repulsion between magnets. Provide examples to illustrate each type of interaction.
Ans:

• Attraction: When opposite poles of two magnets (N-S) are brought close, they pull towards each other.
• Repulsion: When similar poles of two magnets (N-N or S-S) are brought close, they push away from each other.
• Examples: Two magnets can attract each other, as in the case of a fridge magnet sticking to a metal surface. They can also repel each other, like when you try to push the North Poles of two magnets together.

Q6: Describe the process of making a magnet. Explain how a magnetic material can be turned into a magnet using methods like stroking, using an electric current, and using a single touch.
Ans:

• Stroking Method: Rubbing a magnetic material (like iron) with a strong magnet in one direction can magnetize it. The magnetic domains align, making the material a magnet.
• Electric Current Method: Passing an electric current through a coil wrapped around a magnetic material can magnetize it. This method is used to make electromagnets.
• Single Touch Method: Touching a magnetic material with a magnet and then tapping it can magnetize it. Repeating this process strengthens the magnetism.
• Example: Stroking a nail with a bar magnet several times will magnetize the nail, allowing it to pick up small metal objects.

Q7: Explain the concept of a magnetic field and its properties. Describe how the direction of a magnetic field is determined using a magnetic compass.
Ans: A magnetic field is the region around a magnet where its magnetic influence is felt. It has both direction and strength.
Direction of Magnetic Field: A magnetic compass helps determine the direction of a magnetic field. The North Pole of a compass points towards the South Pole of a magnet and vice versa.
Properties of Magnetic Field:

• Stronger Near Poles: The magnetic field is strongest near the poles of a magnet.
• Weaker Farther Away: The magnetic field weakens as you move farther from the magnet.
• Example: If you bring a compass close to a bar magnet, the compass needle will align itself with the magnetic field, showing the direction from the North Pole of the compass to the South Pole of the magnet.

Q8: Explain the concept of the use of magnets in various devices. Provide examples of devices that use magnets and discuss their importance in our daily lives.
Ans: Magnets are used in various devices due to their attractive and repulsive properties.
Examples include:

• Electric Bells: Magnets attract a metal piece to create sound.
• Speakers: Magnets move a coil to produce sound.
• Refrigerator Doors: Magnets hold doors shut.
• MRI Machines: Strong magnets help in medical imaging.

Magnets enhance the functionality of these devices, making them more efficient and useful in our daily lives.

Q9: Explain the working of an electromagnet. Describe the process of making an electromagnet using a coil of wire, an iron core, and an electric current. Provide examples of applications of electromagnets.
Ans: An electromagnet is a temporary magnet created by passing an electric current through a coil of wire wrapped around an iron core.
Making an Electromagnet:

• Wrap a coil of wire (insulated) around an iron core.
• Connect the wire to a battery or power source to pass an electric current.
• The iron core becomes magnetized due to the magnetic field produced by the electric current.

Examples: Electromagnets are used in cranes to lift heavy objects, in doorbells, and in MRI machines for medical imaging.

Q10: Describe the concept of using magnets for separating mixtures. Explain the process of separating mixtures of magnetic and non-magnetic materials using a magnet. Provide examples of mixtures where this process is useful.
Ans:

• Magnetic Separation: Magnets are used to separate mixtures containing magnetic and non-magnetic materials. When a magnet is brought close to the mixture, the magnetic materials get attracted to the magnet, leaving the non-magnetic materials behind.
• Example: Separating iron nails from a mixture of iron nails and sand can be done using a magnet. The magnet attracts the iron nails, allowing them to be easily separated from the sand.