Give reasons for the following.
a) Rain water should be carried out by underground sewer.
b) A bulb get warmer than the wires that connect it to a battery.
c) Soft iron core is used in an electromagnet.
d) Burning of candle is a physical as well as chemical change.
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Please find below the solution to the asked query.
c. We use soft iron for electromagnet as that will help it in making temporary magnets i.e. they should be magnetized as long as current passes through the solenoid wound around them and become demagnetized when no current is passed.
d. Burning of candle is physical as well as chemical change as: -
1) Melting of wax is a physical change as the melted wax can be re-obtained no new substance is formed. The wax melts and turns back into solid state.
2) Burning of wick, Soot and smoke in a candle are chemical changes as these are irreversible and new substances are formed.
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Please find below the solution to the asked query.
c. We use soft iron for electromagnet as that will help it in making temporary magnets i.e. they should be magnetized as long as current passes through the solenoid wound around them and become demagnetized when no current is passed.
d. Burning of candle is physical as well as chemical change as: -
1) Melting of wax is a physical change as the melted wax can be re-obtained no new substance is formed. The wax melts and turns back into solid state.
2) Burning of wick, Soot and smoke in a candle are chemical changes as these are irreversible and new substances are formed.
Kindly ask question in separate thread.
Hope this information will clear your doubts about the topic.
If you have any more doubts just ask here on the forum and our experts will try to help you out as soon as possible.
Regards.