A copper wire of length 1m and radius 1mm is connected in series with another wire of iron of length 2 m and radius 3 mm. A steady current is passed through this combination. The ratio of current densities in copper and iron wires will be

One end of a horizontal thick copper wire of length 2L and radius 2R is weded to an end of another horizontal thin copper wire of length L and radius R .When the arrangement is stretched by applying forces at two ends , the ratio of the elongation in the thin wire to that in the thick wire is

One end of a horizontal thick copper wire of length 2L and radius 2R is welded to an end fo another horizontal thin copper wire of lenth L and radius R. When the arrangement is stretched by applying forces at two ends, the ratio of the elongation in the thin wire to that in the thick wire is

Nichrome and copper wires of same length and same radius are connected in sereis. Current is I passed through them. Which up more ? Justify your answer.

A wire of length 1 m and radius 0.1mm has a resistance of 100(Omega) .Find the resistivity of the material .

The same mass of copper is drawn into two wires 2 mm and 3mm thick. The two wires are connected in series and current is passed through them. The ratio of heat produced in the two wires is

An aluminium wire 7.5 m long is connected in parallel with a copper wire 6 m long. When a current of 5 A is passed through the combination, it is found that the current in the aluminium wire is 3 A . The diameter of the aluminium wire is 1 mm . Determine the diameter of the copper wire. Resistivity of copper is 0.017 muOmega-m and that of the aluminium is 0.028 muOmega-m .

When a wire is wound around a soft iron bar, and a current is passed through it, the soft iron bar behaves like a magnet.

The same mass of aluminium is draw into two wires 1mm and 2mm thick . Two wires are connected in series and current is passed through them. Heat produced in the wires is in the ratio.

A copper wire of radius 0.1mm and resistance 1k(Omega) is connected across a power supply of 20 V.(a)How many electrons are transferred per second between the supply and the wire at one end?(b) Write down the current density in the wire.

A force F is needed to break a copper wire having radius R. The force needed to break a copper wire of same length and radius 2R will be