Friday, September 19, 2014

LESSON 10: SOME PROPERTIES OF SUBSTANCES SMITA

               LESSON 10 : SOME PROPERTIES OF SUBSTANCES          

Q1 Which substances are said to be good conductor of heat  &electricity ?

A   Some substances have the capacity to conduct or carry heat  & electricity.Such substances are called good conductors of heat & electricity.For example copper ,gold ,silver,iron and aluminium are good cnductors of heat  & electricity.


Q2 Which substances are said to be bad conductors of heat & electricity ?

A   Some substances do not have the capacity to conduct or carry heat & electricity. Such substances are called bad conductors of heat & electricity.For example plastic,rubber,wood,paper,acrylic and cloth are bad conductors of heat & electricity.

Q3 What are magnetic substances ?

A  Substances which are attracted to a magnet are called Magnetic substances. for e.g nickel,iron and cobalt are magnetic.

Q4What are Non-magnetic substances ?

A Substances which are not attracted to a magnet are called Non-Magnetic substances. for e.g sawdust,copper,zinc ,gold,silver   & ,aluminium are Non-Magnetic.

Q5 Give the uses of magnets ?

A  1)Motors,generators and loudspeakers have powerful magnets.
     2)In srap yards magnet are used to separate iron & steel from the junk.
     3)Hard disks,floppies,audio video tapes are also coated with magnetic materials.
     4)Information is stored on magnetic strips in credit cards & airline tickets.
Motors, generators

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