Black Stone discovered by Greeks is called as Magnetite
Magnetite is made up of chemical called Iron oxide
Why have they named it as Loadstone?
- They named magnet as lead loadstone which means leading stone.
- Loadstone shows the direction since it shows, North-South direction when suspended freely.
What are called as Magnetic substances?
- Substances attracted by Magnet are called as Magnetic substances
- Ex: Iron, Nikal, Cobalt, Steel
What are Non Magnetic substances?
- Substances not attracted by Magnet are called as Non Magnetic substances
- Ex: Gold, Silver, Aluminium, Wood, Rubber.
List some of the common characteristics of Magnet?
- Magnets are usually in form of bar magnet, Horse Shoe magnet.
- Poles of magnet attract more Iron filling than centre.
- Freely suspended magnet always points North & South direction.
What are the Poles of Magnet?
- North seeking pole is North pole of magnet.
- South seeking Pole is south pole of magnet.
What do you observe when magnets are cut into two?
- When a magnet is cut into two, that we know
- Poles exist in pairs.
- We can never have separate North pole and South Pole.
- Like poles repel each other.
- Unlike poles attract each other
What are the four properties of magnet?
- Attractive property
- Directive property
- Repulsive & Attractive property.
- Magnet poles exist in pair.
What are the various shapes of magnet?
- Bar magnet
- Magnetic needle
- Horseshoe magnet.
- Ring magnet
- Disc magnet
Why does a suspended magnet always show the North and South direction?
- Earth itself behaves as a bar property magnet with magnetic poles near geographical North & South poles.
- When we suspend a bar magnet, North pole of magnet south pole is attracted to Earth geographical South pole
What is Magnetic compass?
- Magnetic compass are used to show direction
- It mainly used by sailors.
- Magnetic compass needle always points NORTH direction.
What are the two methods used to make magnet?
Methods used to make magnet is
- Single Touch method
- Electric current.
What is Aurora?
Earth Magnetic pole attract some special particle from sun, these react with air and produce. coloured light. It is called as Aurora
How a magnet can be demagnetised?
A magnet can be demagnetised by
- Forcibly beaten by hammer
- When it Falls from a height
- When heated to higher temperatures.
- When magnets are left free, they become. weaker, it undergoes self-demagnetisation
What are Magnetic keepers?
- Magnets are stored using Keepers
- Keepers are pieces of iron, placed across both ends.
- Two Bar magnets are kept in pairs separated by piece of wood.
- Bar magnet needs two keepers, Horse Shoe magnet needs only one keeper across its poles.
List the various uses of magnets?
- Refrigerator door, bulletin boards, toys contains magnets.
- Electric motors used in Fans, bicycle, automobile dynamos used for making electricity contain magnets.
- Magnets used in speakers, microphone, computer monitor, Picture tube of television.
- Magnets are used in audio, video tap, computer hard disk to store information.
- In credit cards, ATM cards, information is stored in magnetic strip.
- Super conducting magnets are used in MRI Machines, scientific equipment.
Define Magnetic field of magnet?
Region around magnet where the magnetic field is influenced is called as Magnetic field of the magnet.
What are the properties of Magnetic field?
- The magnetic field line is a closed & continuous curve.
- Magnetic Field lines never intersect.
- The magnetic line originates at the north pole & moves towards the south pole outside the magnet and from the south pole to the north pole inside it.
Given a Bar magnet, How will you find west. direction?
- First suspend the bar magnet.
- At rest, it will be in N-S direction.
- Left side of it East, Right side is West.
How many types of magnets are there?
- Permanent magnet, Temporary Magnet, Electromagnet.
- Permanent magnets are the one that do not lose their magnetic property. once they are magnetized.
- Temporary Magnetic property is created in presence of magnetic field. when the Magnetic field is removed, they lose their magnetic property eg. Iron nail, paper
- Electromagnet are created when electric wire is passed through coil of wire wrapped around metal core made from Iron.
- Strength of magnetic field is controlled by electric current
Rate this post
If unable to download Click here
Useful Links: