A rectangular piece of land measures 0.7 km by 0.5 km.Each side is to be fenced with 4 ows of wires.What length of the wire is needed?

A solid lead ball of radius 7 cm is melted is converted into a wire of diameter 0.2 cm. find its length of the wire.

A piece of ductile metal is in the formof a cylinder of diameter 1 cm and length 5 cm. It is drawn out into a wire of diameter 1 mm. What will be the length of the wire so obtained ?

A wire is in the shape of a rectangle. Its length is 40 cm and breadth is 22 cm. If the same wire is rebent in the shape of a square, what will be the measure of each side. Also find which shape encloses more area?

Shazli took a wire of length 44 cm and bent it into the shape of a circle. Find the radius of that circle. Also find its area. If the same wire is bent into the shape of a square, what will be the length of each of its sides? Which figure encloses morearea, the circle or the square? (Take pi = 22/ 7 )

A uniform conducting wire of length 12a and resistance R is wound up as a current carrying coil in the shape of a square of side a. The coil is connected to a voltage source V_0 . Find the magnetic moment of the coils in each case.

A straight horizontal conducting rod of length 0.45 m and mass 60 g is suspended by two vertical wires at its ends. A current of 5.0 A is set up in the rod through the wires. What will be the total tension in the wires if the direction of current is reversed keeping the magnetic field same as before? (Ignore the mass of the wires.) g = 9.8 m s^-2 .

A steel wire has a length of 12.0 m and a mass of 2.10 kg. What should be the tension in the wire so thatspeed of a transverse wave on the wire equalsthe speed of sound in dry air at 20 ^@C = 343 m s^-1 .