How does the resistance of a wire change when:

(i) its length is tripled?


(ii) its diameter is tripled?


(iii) its material is changed to one whose resistivity is three times?

(i) The resistance of a wire is directly proportional to its length and inversely proportional to its area (or square of inverse of diameter). When the length is tripled then its resistance will also becomes three times

(ii) If the diameter get tripled then its resistance becomes one ninth of the initial resistance.


(iii) If the material is changed to one whose resistivity is three times then again its resistance will be three times


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