Question

Q13. Two wires A and B are of equal lengths, different cross-sectional areas and made of the same metal.

(i) Name the property which is same for both the wires.

(ii) Name the property which is different for both the wires.

(iii) If the resistance of wire A is four times the resistance of wire B, calculate

(a)the ratio of the cross-sectional areas of the wires.

(b)the ratio of the radii of the wires.

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Answer 1

Answer:

Two wires A and B are of equal length, different cross – sectional areas and made of the same metal                                                                                                                                                                       (A) Name the property which is same for both the wires    

Answer: As the resistivity is independent of cross – sectional areas resistivity is same for both the wires                                                                                                              

(B) Name the property which is different for both the wires

Answer:  As the resistance of the material depends on both the length and cross sectional area of the wire resistance changes.        

(C) If the resistance of the wire A is 4 times the resistance of wire B, Calculate the ratio of the radii of the wires.

Answer:    

As the resistance is inversely proportional to the square of the radius of the conductor,

Ratio of the radii of the wires is RB : RA = 2:1

Explanation: