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The resistance of a 10m long wire of a particular material is 5 ohm .what will be the resistance:​​ Of a 20m long wire of the same material and radious? Of a wire of length 10m but double the area cross-section?

  1. The resistance of a 10m long wire of a particular material is 5 ohm .what will be the resistance:​​
  • Of a 20m long wire of the same material and radious?
  • Of a wire of length 10m but double the area cross-section?

Grade:10

1 Answers

Sanju
106 Points
6 years ago
We have, Resistance = Resistivity * (length/area)
  1. When l = 20 (keeping the material and radius unchanged), resistance becomes 10 ohm. Resistance and length of the wire have proportional relationship. Doubling the length (keeping the material and radius unchanged) therefore increases the resistance of the wire by two fold. [i.e., Resistance doubles]
  2. When the area of cross section is doubled, the resistance gets reduced by half since the relation between resistance and area is inversely proportional.. That is, it becomes 2.5 ohm.

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