The electrical resistance $“R”$ of a metal is given by the formula:
$$ R = p (l/A) $$
The table below shows the electrical resistance of a wire (made of metal “Z”) of length “l” and cross-sectional area “A”, at different temperatures.
|Temperature||Resistance (in ohm)|
The table below shows the resistances of wires of different lengths made out of the same metal (Z) at 20° C. The cross-sectional area of these wires is equal.
|Length (in meter)||Resistance (in ohm)|
The table below shows the resistances of wires of different cross-sectional areas made of the same metal (Z) at 20° C. The length of these wires is equal.
|Cross sectional area (in 10-8 m$^2$)||Resistance (in ohm)|
Which of these is the correct plot of the change in resistance of a wire with change in the radius of its cross section?
(Length of the wire and the temperature are constant).