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 ?
CBSE Class X Science SA 2 (3 Marks)
Answers
Answered by
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(1) These are good conductors of electricity/low resistance/low resistivity.
(ii)Very high melting point and high resistivity.
(iii) Low melting point.
Answered by
14
1. They are very good conductors of electricity and offer almost negligible resistance. It is used often due to nil wastage of energy in the form of heat.
2. They offer very high resistivity and can withstand temperatures of more than 2000 deg. celsius giving more light but heats up a lot.
3. Used due to low melting points. Whenever there is a sudden increase in current due to any kind of impulse, it cannot withstand it and just melts to prevent short circuit or harm to other appliances.
2. They offer very high resistivity and can withstand temperatures of more than 2000 deg. celsius giving more light but heats up a lot.
3. Used due to low melting points. Whenever there is a sudden increase in current due to any kind of impulse, it cannot withstand it and just melts to prevent short circuit or harm to other appliances.
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