📘 Welcome
Hi User, you have selected Read Mode.
This is Time Free Mode for your convenience to understand every question as per your Ease and Time.
Here You get Answer and Details button. After mastering this mode, you can go for a test with Test Mode on the main page designed especially with Exam Features.
This is Time Free Mode for your convenience to understand every question as per your Ease and Time.
Here You get Answer and Details button. After mastering this mode, you can go for a test with Test Mode on the main page designed especially with Exam Features.
Q1. The first known direction-indicating device was invented by:
Hoang Ti, also known as the Yellow Emperor, is believed to have invented the first direction-indicating chariot in ancient China around 2600 BCE. This chariot used a mechanical figure that always pointed south, regardless of how the chariot turned. It was one of the earliest navigation devices before the magnetic compass was invented.
Q2. Hoang Ti’s direction-indicating chariot worked on the principle of:
Hoang Ti’s chariot did not use magnetism but used a complex system of gears and a differential mechanism. The gears were arranged so that the pointing figure would always turn to face south, even when the chariot changed direction. This was a remarkable engineering achievement for its time.
Q3. The direction-indicating chariot of Hoang Ti is also known as the:
Hoang Ti’s invention is called the South-pointing chariot because the figure on it always pointed towards the south. This was useful for travelling in unknown territories and for military purposes. It was one of the earliest examples of a mechanical navigation device.
Q4. The device that always pointed south in Hoang Ti’s chariot was:
The south-pointing chariot had a mechanical wooden figure mounted on top that always pointed south. This was achieved through a system of gears that kept the figure oriented in the same direction. The figure was not magnetic but worked on purely mechanical principles.
Q5. The simplest way to make a magnet at home is by:
The simplest way to make a magnet at home is by rubbing a piece of iron or steel with a strong magnet in one direction. This process aligns the magnetic domains inside the iron and makes it magnetic. When rubbed repeatedly, the iron piece becomes a temporary magnet.
Q6. The process of making a magnet by rubbing is called:
Magnetization is the process of making a magnetic material into a magnet. When an iron or steel object is rubbed with a magnet, the domains inside it align in a particular direction, turning it into a magnet. This is the simplest method of making a magnet at home.
Q7. To make a magnet by rubbing, you should rub the iron piece:
To magnetize an iron piece, you should rub it with a magnet in the same direction repeatedly, about 30 to 40 times. This ensures that all the magnetic domains align in a single direction, creating a proper magnet. Rubbing in random directions will not produce a strong magnet.
Q8. When making a magnet by rubbing, the end where the rubbing ends becomes the:
When you rub an iron piece with the North pole of a magnet, the end where the rubbing ends becomes the North pole of the newly created magnet. The opposite end becomes the South pole. This is because the magnetic domains align according to the direction of the magnetic field.
Q9. A magnetic compass can be made using:
A simple magnetic compass can be made by magnetizing a sewing needle by rubbing it with a magnet. The magnetized needle is then placed on a floating piece of cork in a bowl of water. The needle aligns itself in the North-South direction, acting as a compass.
Q10. To make a simple compass, you need a magnetized needle, a cork and:
To make a simple compass, you place the magnetized needle on a small piece of cork and float it in a bowl of water. The cork and needle rotate freely until the needle points North-South. The water reduces friction, allowing the needle to align with the Earth’s magnetic field.
Q11. If you place a magnetized needle on a cork in water, it will align itself in the:
When a magnetized needle is floated on water, it rotates freely until it aligns itself in the North-South direction. This happens because the needle acts as a small magnet and responds to the Earth’s magnetic field. This is the basic principle of a magnetic compass.
Q12. A simple compass works because:
A simple compass works because the Earth’s magnetic field exerts a force on the magnetized needle. This force causes the needle to rotate until it aligns with the magnetic field lines, pointing towards the magnetic North and South. This is why the needle always points in the North-South direction.
Q13. When the North pole of a magnet is brought near the North pole of another magnet, they:
Like poles of magnets, such as North-North, always repel each other because their magnetic fields push against each other. The magnetic field lines try to avoid each other, causing the magnets to move apart. This repulsion is a fundamental property of magnetism.
Q14. When the South pole of a magnet is brought near the South pole of another magnet, they:
Like poles, such as South-South, always repel each other because their magnetic fields are similar and oppose each other. The magnetic field lines cannot cross, so the magnets push each other away. This shows that like poles always repel.
Q15. When the North pole of a magnet is brought near the South pole of another magnet, they:
Unlike poles, such as North-South, always attract each other because their magnetic fields complement each other. The magnetic field lines go from the North pole of one magnet to the South pole of the other, pulling them together. This attraction is the strongest force between magnets.
Q16. The rule of attraction and repulsion between magnets is:
The basic rule of magnetism is that like poles (North-North or South-South) repel each other, while unlike poles (North-South) attract each other. This rule applies to all magnets, whether natural or artificial. Understanding this rule helps us understand how magnets interact.
Q17. The surest test to check whether an iron piece is a magnet or not is:
The surest test to check if an iron piece is a magnet is to bring another magnet near it. If the iron piece repels the magnet, it is definitely a magnet because only like poles repel. Attraction alone is not a reliable test because non-magnetic iron pieces can also be attracted to a magnet.
Q18. If an iron piece attracts another iron piece, it could be:
If an iron piece attracts another iron piece, it could be a magnet, but it could also be a non-magnetic iron piece that is being attracted by a magnet nearby. This is why attraction alone is not a sure test. The sure test is repulsion, which only happens between two magnets.
Q19. To test if an iron piece is a magnet, you should:
The best way to test if an iron piece is a magnet is to bring it near a known magnet and check if it repels. If it repels, it is definitely a magnet because only like poles repel. Attraction is not a reliable test because non-magnets can also be attracted.
Q20. A non-magnetic iron piece is attracted to a magnet but:
A non-magnetic iron piece can be attracted to a magnet, but it will never repel another magnet. This is because repulsion only occurs when two magnets with like poles are brought together. Therefore, repulsion is the sure test to identify a magnet.
Q21. The magnetic force of a magnet can pass through:
The magnetic force of a magnet can pass through non-magnetic materials like paper, glass, plastic and wood. This property is used in many everyday situations, such as holding a note on a refrigerator door with a magnet. The magnetic field penetrates these materials without being weakened.
Q22. A magnet can attract an iron nail even if there is a:
A magnet can attract an iron nail even if there is a plastic, glass or paper sheet between them. This is because the magnetic field can pass through non-magnetic materials without losing its strength. However, the magnetic force becomes weaker as the distance increases or if thick materials are used.
Q23. Magnetic effects can pass through screens because:
Magnetic effects can pass through screens because magnetic fields can penetrate non-magnetic materials like paper, plastic, glass and wood. This is why a magnet can attract iron objects even when they are separated by these materials. However, magnetic screens made of iron or steel can block the magnetic field.
Q24. Which material can act as a screen to stop magnetic effects?
Iron and steel can act as magnetic screens because they are magnetic materials and can absorb or redirect the magnetic field. When a magnetic material is placed between a magnet and another object, it blocks the magnetic force. This property is used to protect sensitive instruments from magnetic interference.
Q25. A magnetic screen is used to:
A magnetic screen is a piece of magnetic material, usually iron or steel, used to block or reduce the magnetic field. It is placed around sensitive devices like watches, compasses and electronic equipment to protect them from external magnetic fields. This helps in maintaining the accuracy of these devices.
Q26. A magnetic keeper is a piece of:
A magnetic keeper is a piece of soft iron that is placed across the poles of a magnet when it is not in use. It helps to retain the magnetic strength of the magnet by providing a path for the magnetic field lines. Without a keeper, magnets tend to lose their magnetism over time.
Q27. The purpose of a magnetic keeper is to:
A magnetic keeper is used to prevent a magnet from losing its magnetism when stored. It completes the magnetic circuit, keeping the magnetic field lines confined to the magnet. This is particularly important for storing bar magnets and horseshoe magnets.
Q28. A keeper is placed across the poles of a magnet to:
A keeper is placed across the poles of a magnet to complete the magnetic circuit. This provides a path for the magnetic field lines to flow, reducing the loss of magnetism. The keeper is usually made of soft iron, which is a good magnetic conductor.
Q29. Two bar magnets are stored with their unlike poles together and a keeper placed across them to:
When two bar magnets are stored with unlike poles together and a keeper placed across them, the magnetic circuit is completed. This arrangement keeps the magnetic field lines confined within the magnets and the keeper, preventing the magnets from losing their strength. This is the correct way to store magnets.
Q30. A keeper is made of soft iron because:
A keeper is made of soft iron because it is a good conductor of magnetic field lines. Soft iron is easily magnetized and demagnetized, making it ideal for use as a keeper. It provides an easy path for the magnetic field lines to flow, which helps in preserving the magnetism of the magnet.
Q31. If you store a bar magnet without a keeper, it will:
If a bar magnet is stored without a keeper, it will slowly lose its magnetism over time. This happens because the magnetic field lines are not confined and can spread out, causing the magnetic domains to become misaligned. Using a keeper helps maintain the magnet’s strength for a longer time.
Q32. Hoang Ti’s south-pointing chariot was an invention used in:
Hoang Ti’s south-pointing chariot was invented in ancient China around 2600 BCE. It was used for navigation and military purposes. This invention shows that people were finding ways to navigate long before the discovery of the magnetic compass.
Q33. The south-pointing chariot was not a magnetic device because:
The south-pointing chariot was not a magnetic device because it did not use a magnet or magnetic compass. Instead, it used a complex system of gears and a differential mechanism to keep the pointing figure always facing south. It was a purely mechanical invention.
Q34. The direction-indicating chariot was also used to:
The direction-indicating chariot was used to find directions, especially during travel and military campaigns. It helped people know which way was south, which was important for navigation. This was very useful in ancient times when there were no modern navigation tools.
Q35. The figure on Hoang Ti’s chariot always pointed:
The mechanical figure on Hoang Ti’s chariot always pointed towards the south, regardless of the direction the chariot was moving. This made it a “south-pointing” chariot, helping travellers know their direction. The south-pointing feature was important because south was a significant direction in Chinese culture.
Q36. When an iron piece is rubbed with a magnet, the end of the iron piece that is rubbed first becomes the:
When an iron piece is rubbed with a magnet, the end where the rubbing begins becomes the South pole, and the end where the rubbing ends becomes the North pole. This depends on the direction of rubbing and the pole of the magnet used. The domains align according to the direction of the magnetic field.
Q37. A magnetized needle can be used as a compass because:
A magnetized needle acts as a compass because it aligns itself with the Earth’s magnetic field. The needle is a small magnet that rotates to point towards the magnetic North and South poles. This property makes it useful for finding directions.
Q38. The Earth’s magnetic field causes a compass needle to:
The Earth’s magnetic field causes a compass needle to align itself in the North-South direction. The needle rotates until its North pole points towards the Earth’s magnetic North pole. This is the fundamental principle behind the working of a magnetic compass.
Q39. If you bring the South pole of a magnet near the North pole of another magnet, they will:
Unlike poles attract each other. When the South pole of one magnet is brought near the North pole of another magnet, they will pull towards each other. This attraction is due to the magnetic field lines flowing from the North pole of one magnet to the South pole of the other.
Q40. The magnetic force can pass through non-magnetic materials because:
Magnetic force can pass through non-magnetic materials like paper, plastic and wood because these materials do not block magnetic fields. The magnetic field lines pass through these materials without being absorbed or weakened significantly. This is why a magnet can hold a note on a refrigerator door through a piece of paper.
Q41. The magnetic field is not affected by:
Wood is a non-magnetic material, so it does not affect the magnetic field. The magnetic field lines can easily pass through wood without being blocked or changed. However, magnetic materials like iron, steel and cobalt can affect and even block the magnetic field.
Q42. A strong magnet can attract an iron nail through:
A strong magnet can attract an iron nail through a glass plate, a wooden plank or a paper sheet because these are non-magnetic materials. The magnetic field can penetrate these materials, allowing the force to reach the iron nail. However, the distance and thickness of the material can weaken the force.
Q43. When two magnets are placed with their like poles together, they:
When two magnets are placed with their like poles together, they repel each other or push each other away. This happens because their magnetic fields oppose each other and try to move apart. This repulsion is a clear indication of like poles.
Q44. When two magnets are placed with their unlike poles together, they:
When two magnets are placed with their unlike poles together, they attract each other or pull towards each other. This happens because their magnetic fields complement each other and the field lines join together. This attraction is the strongest when the magnets are close.
Q45. To preserve the magnetism of a horseshoe magnet, you should use a:
To preserve the magnetism of a horseshoe magnet, you should use a soft iron keeper. The keeper is placed across the two poles of the magnet, completing the magnetic circuit. This prevents the magnet from losing its magnetism over time.
Q46. The magnetic keeper is placed across the poles of a magnet to:
A magnetic keeper is placed across the poles of a magnet to complete the magnetic circuit and preserve its magnetism. This provides a path for the magnetic field lines, preventing them from spreading out and weakening the magnet. This is the correct way to store magnets.
Q47. A soft iron keeper is used instead of a steel keeper because soft iron:
Soft iron is used for keepers because it is easily magnetized and demagnetized. This means it can be magnetized by the magnet it is placed on and demagnetized easily when removed. Steel, on the other hand, remains magnetized, which is not desirable for a keeper.
Q48. When a magnet is stored without a keeper, the magnetic domains inside it become:
When a magnet is stored without a keeper, the magnetic domains inside it gradually become misaligned. This happens because the magnetic field lines are not confined and can spread out, causing the domains to lose their alignment. Over time, this misalignment causes the magnet to lose its magnetic strength.
Q49. The direction-indicating chariot was not widely used because:
The direction-indicating chariot was eventually replaced by the magnetic compass, which was simpler and more accurate. The magnetic compass did not require complex mechanical parts and could be easily carried. This made it much more practical for navigation.
Q50. A magnet kept with a keeper will:
A magnet kept with a keeper will retain its magnetism for a longer time because the keeper completes the magnetic circuit. This prevents the magnetic domains from becoming misaligned. Proper storage with a keeper is essential for maintaining the strength of magnets, especially bar and horseshoe magnets.
________________________________________
________________________________________
Q51. The repulsion between two magnets is a proof that:
Repulsion between two magnets is a definite proof that both objects are magnets. Unlike attraction, which can also happen between a magnet and a non-magnetic piece of iron, repulsion only occurs when two magnets with like poles are brought together. This is why repulsion is called the sure test of magnetism.
Q52. The needle of a compass is made of a magnetic material so that it:
The needle of a compass is made of a magnetic material so that it can respond to the Earth’s magnetic field. This allows the needle to align itself in the North-South direction. Without being magnetic, the needle would not be able to find directions.
Q53. The magnetic field of a magnet can be blocked by a:
The magnetic field of a magnet can be blocked by an iron screen because iron is a magnetic material that absorbs and redirects the magnetic field lines. Non-magnetic materials like paper, plastic and wood do not block the magnetic field. This property is used in magnetic shielding to protect sensitive equipment.
Q54. Hoang Ti’s south-pointing chariot was invented because:
Hoang Ti’s south-pointing chariot was invented because the magnetic compass had not yet been discovered. People needed a way to navigate, so they created mechanical devices like this chariot. It was a clever solution before the discovery of magnetic navigation.
Q55. The process of making a compass using a magnetized needle and a bowl of water works because:
The process of making a compass using a magnetized needle and a bowl of water works because the needle is magnetic. The magnetized needle aligns itself with the Earth’s magnetic field, pointing North-South. The water allows the needle to rotate freely without friction.
Q56. A simple compass made with a magnetized needle and a cork in water will:
A simple compass made with a magnetized needle and a cork in water will point North-South because the needle aligns itself with the Earth’s magnetic field. The water and cork allow the needle to rotate freely until it finds the correct direction. This is a simple and effective way to make a compass.
Q57. When you rub an iron piece with a magnet, the iron piece becomes a magnet because:
When you rub an iron piece with a magnet, the magnetic domains inside the iron align themselves in the same direction. This alignment causes the iron piece to become a magnet. The magnetism is induced by the external magnetic field of the rubbing magnet.
Q58. A keeper is used with a magnet to:
A keeper is used with a magnet to complete the magnetic circuit, providing a path for the magnetic field lines to flow. This helps prevent the magnet from losing its magnetism when stored. The keeper is usually placed across the poles of the magnet.
Q59. If you store two bar magnets with their like poles together and no keeper, they will:
If you store two bar magnets with their like poles together, they will repel each other and may even push apart. This is not a proper way to store magnets because it can cause them to lose their magnetism. The correct way is to store them with unlike poles together and with keepers.
Q60. The correct way to store two bar magnets is to place them:
The correct way to store two bar magnets is to place them with unlike poles together and a soft iron keeper across them. This arrangement completes the magnetic circuit and preserves the magnetism of both magnets. Proper storage is essential to maintain the strength of magnets.