Question

Two wires A and b are of equal length, different cross sectional areas and
made of same metal.
(a) (i) Name the property which is same for both the wires.
(11) Name the property which is different for both the wires.
(b) If the resistance of wire A is four times the resistance of wire B, calculate
(i) the ratio of the cross sectional areas of the wires and
(ii) the ratio of the radii of the wire.
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Answer 1

Answer:

Explanation:

a)1)Resistivity-The resistivity being the property of the material will be same.

a)2)Resistance- As both the wires are of different cross-sectional area, their resistances are different (r∝1/A)

b)1)Resistance is inversely proportional to the area of cross section of the conductor.   Thus since the resistance of A is 4 times the resistance of B, hence the ratio of area of   cross-section of A to B will be 1:4

b)2) Ratio of radii of wire is square root the ratio of area (because r=A/pi) thus ratio of radii will be 1:2