i. An object that attracts materials like iron, nickel and cobalt is called a magnet.
ii. A magnet has two poles – North Pole and South Pole.
iii. Magnetite is a natural magnet.
iv. A compass can be used to find directions.
v. Temporary magnets retain their properties only for a short period of time.
i. A cylindrical magnet has only one pole. False
ii. The force of attraction of magnet is maximum at the poles and minimum at the centre. True
iii. Plastic is a magnetic material. False
iv. The earth behaves like a giant magnet. True
v. We can make magnet with single pole. False
Ans. A shepherd named Magnes discovered magnets.
Ans. At the two ends.
Ans. At poles
Ans. Mixture of iron fillings and sand can be separated by using magnet.
Ans. The force is weaker in the middle of the magnet.
Ans. A freely suspended magnet comes to rest in north - south direction.
Ans. When we bring a magnet close to it, the needle gets deflected.
Ans. The two poles of a magnet are North Pole and South Pole.
Ans. Magnet may have lost its properties.
Ans. The two magnets will repel each other as like poles repels.
Ans. A magnet can be demagnetized by heating, hammering or dropping from some height.
Ans. If a particular substance is attracted towards a magnet, then it is a magnetic substance and if it is not attracted towards a magnet, then it is a non-magnetic substance.
Ans. Devices such as mobiles, television, computers and CD are made up of magnetic material and have magnets in it. If we keep magnets near them, magnet may spoil these devices.
Ans. Even a smallest piece of a magnet has north and south poles and we cannot separate the two poles. Therefore, poles always exist in pairs. That is why a magnet is called a "magnetic dipole”.
Ans. Electromagnet is a magnet made by passing electric current through a soft metal surrounded by a coil. The magnetic field disappears when the current is turned off.
Ans. Each one has a north and south pole. Or, we can say, that the end that was pointing south will be South Pole and its opposite end will be a new north pole.
Ans. Magnets lose their properties if they are heated, hammered or dropped from some height. Also, magnets become weak if they are not stored properly.
Download to practice offline.