Two wires of equal length, one of aluminium an the other of copper have the same resistance. Which of the two wires is lighter ? Hence explain why aluminium wires are preferred for overhead power cables.
`(rho _(AI) =2.63 xx 10 ^(-8) Omega m, rho _(Cu) =1. 72 xx 10 ^(-8) Omega m.` Relative density of `Al =2. 7 of Cu =8.9.`)

Two copper wires, one of length 1 m and the other of length 9m have the same resistance. The diameter in the ratio

Two wires have same length. But area of cross-section of one is 4 times that of the other. If the resistance of thinner wire be 200 Omega the resistance of the thicker wire is

There are two metallic wires of the same thickness made from iron and silver. If the length of iron wire is 12cm, what should be the length of silver wire which is equal to the resistance of iron wire? Data : Resistivity of iron = 10 xx 10^(-8) Omega m Resistivity of silver = 16 xx 10^(-8) Omega m

The resistance offered by a wire of unit length and unit cross-sectional area is called resistivity. For a material irrespective of length and area, the resistivity is constant. It is also called specific resistance of the material. Metals and alloys have low resistivity while insulators have high resistivity. Resistivity of two elements A and B are 1.62 xx 10^(-8) Omega m and 520 xx10^(-8) Omega m respectively. Out of these two, name the element that can be used to make : (i) filament of electric bulb. (ii) wires for electrical transmission lines.

Calculate the resistance of a metal wire of length 2 m and area of cross section 1·55 xx 10^(-6) m^(2) , if the resistivity of the metal be 2·8 xx 10^(-8) Omega m ?

100 mg mass of nichrome metal is drawn into a wire of area of cross-section 0.05 mm. Calculate the resistance of this wire. Given density of nichrome 8.4 xx 10^3 "kgm"^(-3) and resistivity of the material as 1.2 xx 10^(-6) Omega m.