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Give reason for the following:
(i) Why are copper and aluminium wires used as connecting wires?
(ii) Why is tungsten used for filament of electric lamps? (iii) Why is lead-tin alloy used for fuse wires?
Answer:
(a)
Copper and aluminium are good conductors of electricity.
They have very low resistance and allow the current to flow through them easily.
Hence, they are used to make wires for electrical transmissions.
(b)
Tungsten metal is used exclusively for making the filament of electric bulbs because it has a very high melting point.
Due to its high melting point, the tungsten filament can be kept white hot without melting away.
Other reasons for using tungsten are
- It is highly flexible
- It has a low rate of evaporation at high temperature.
(c)
Lead-tin alloy is used for fuse wire because of its high resistivity and low melting point .
