When two conducting wires used to attract each other?

The lengths radii and specific resistance of two conducting wires are each in the ratio of 1:3. If the resistance of the thinner wire is 10 Omega then the resistance of the other wire will be

Two long straight conducting wires ara kept parallel to each other at a distance r apart. When a current I passes through both the wires in the same direction, a force of attraction vecF acts between the wires. Which of the following statement is/are true?

Two parallel conductors carrying currents in the same direction attract each other-explain with reason.

State whether True or False : When two materials are rubbed against each other one becomes positively and the other becomes negatively charged.

When two charged conductors are joined by a thin conducting wire, charge flows from one to the orhter, until

Two very long conducting wire are kept at a distance 4 cm from each other in vacuum. Currents flowing through the wires are 25A and 5A, respectively. Find the length of each conductor, which experiences a force of 125 dynes ?

Two small metal spheres of equal volume are oppositely charged and are kept 0.5 m apart in vaccum. The attractive force between them is 0.144 N. But a repulsive force of 0.081 N acts between them after they are momentarily connected with a conducting wire. Find out the initial charges on the two spheres.

If the length of a conducting wire be doubled by stretching, its resistance compared to the initial value will be :

Two indentical long conducting wires AOB and COD are placed at right angles to each other, with one above other such that is their common point for the two. The wires carry I_(1) and I_(2) currents respectively. A point P is at a height d above the point O, with respect to the plane of the wires. the magnetic field at P is,