A copper wire of length 1m and radius 1mm joined in series with an iron wire of length 2m and radius 3mm and a current is passed through the wire. The ratio of current densities in the copper and iron wire is
(A) 18:1
(B) 9:1
(C) 6:1
(D) 2:3

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

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 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.

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 5m is twisted through 30^(0) at free end If the radius of wire is 1mm , the shearing strain in the wire is

A wire of length 100 m is tightly wounded on a hollow tube of radius 5mm and length 1 m. A current of 1 A is flowing in the wire. Then magnetic field strength inside the tube 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

A copper wire of diameter 6mm is evenly wrapped on the cylinder of length 18cm and diameter 49cm to cover the whole surface. Find: the volume of the wire.

A wire of length 1 m and radius 1mm is subjected to a load. The extension is x .The wire is melted and then drawn into a wire of square cross - section of side 2 mm Its extension under the same load will be

What is the frequency of the fundamental note emitted by a wire of length 2 m and radius 1 mm under a tension of 200 N. Density of the wire is "1600 kg/m"^3.