A wire of resistance 16 ohm is melted and drawn into a wire of half of its original length calculate the resistance of new wire what is its percentage change in resistance
Answers
ANSWER IS-: So the new resistance is 75% less than old resistance.
NEW RESISTANCE IS 4 Ohms
We know that
Resistance = Rho (Resistivity) * Length of Conductor /(Area of Cross-Section)
SO given wire has a resistance of 16 Ohms.
16 = Rho * Length / Area
If the length is halved after melting wire, it means Area of cross section would have doubled..
New resistance = Rho * 1/2 Length / 2*Area of Cross Section
New resistance = Rho * Length / 4* AREA OF Cross Section
16/ New Resistance = (Length of Conductor / Area of Cross - Section) / Length / 4* Area of Cross Section. {rho gets cancelled by rho}
1/New Resistance = 4/16 {Length of conductor and Area of . cross Section also get cancelled}
New Resistance = 4 Ohms...
Percent of Change of Resistance = New Resistance / Old Resistance * 100
4/16*(100) =100/4= 25%
So the new resistance is 75% less than old resistance
I request you to please once verify the calculations as I am not good at calculations...
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Answer:
Explanation: new resistance is 75%