If the resistance of wire A is four times the resistance of wire B, find the ratio of their cross sectional areas.

If the resistance of wire A is three times the resistance of wire B and the two wires have the same length, compare their cross sectional areas. The two wires are made of the same material.

A wire has length 10 m and resistance 20 Omega If the resistivity of the material of the wire is 6 times 10^(-7) Omega.m , find the area of cross section of the wire.

The diameter of iron sphere is 6 cm. It is melted and drawn into a wire having diameter of the cross section as 0.2 cm. Find the length of the wire.

Three long straight wires are connected parallel to each other across a battery of negligible internal resistance. The ratio of their resistances are 3:4:5 . What is the ratio of distances of middle wire from the others if the net forces experienced by it is zero.

When a body falls in air, the resistance of air depends to a great extent on the shape of the body, 3 different shapes are gives. Identify the combination of air resistances which truly represents the physical situation. (the cross sectional areas are the same).

What is the resistance of one of the rails of a railway track 20 km long at 20^@ C? The cross section area of rail is 25 cm^2 and the rail is made of steel having resistivity at 20^@ C as made of steel having resistivity at 20^@ C as 6 xx 10^-8 Omega m.

A wire has radius 0.5 mm and length 62.8 m. If the resistivity of the material of the wire is 5 times 10^(-7) Omega -m , find the resistance of the wire.

A force of 400 kg. weight can break a wire. The force required to break a wire of double the area of cross-section will be

A metal wire of length L_1 and area of cross-section A is attached to a rigid support. Another metal wire of length L_2 and of the same cross-sectional area is attached to free end of the first wire. A body of mass M is then suspended from the free end of the second wire. If Y_1 and Y_2 are the Young's moduli of the wires respectively, the effective force constant of the system of two wire is

Choose correct alternative. Two wires of same material and same length are connected in series. The area of cross section of wires is in ratio 3:1 . The resistance of thicker wire is 10 Omega . The total resistance of combination is