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If a wire of resistance 1 ohm is stretched to double it's lenght then the resistance will become please answer me the perfect answer |
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Answer» 4ohmExplanation:The point here to understand is when we STRETCH a wire we increase is its length and as the volume of the wire is kept constant, so the area of the cross-section of the wire has to be now EXACTLY half of the initial value.Now let us say the original length of wire is '1',the area of cross-section of the wire is 'A' and the RESISTIVITY of the wire is 'P', then ACC. to the formula for resistanceR=P*(I/A)Now after stretching the wire,Length=2*l Area=A/2So the NEW resistanceR'=P*[21/(A/2)]R'=4*[P*(I/A)]R'=4RSo the new resistance is 4 times the initial resistance. |
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