In: Physics
A long horizontal wire carries a current of 48 A. A second wire, made of 2.7 mm diameter copper wire and parallel to the first, is kept in suspension magnetically 15 cm below. Determine the magnitude of the current in the lower wire. Determine the direction of the current in the lower wire. IS IT IN STABLE EQUILIBRIUM?
Magnetic force between two wire separated by a distance r is given by
where i1 and i2 are the current through the wires.
The second wire is in suspension magnetically.
Hence the magnetic force between the wires must be equal to the weight of the 2nd wire.
To support the 2nd wire situated below magnetic force must be upwards and hence flow of the current in both the wire must be same and towards the right.
d is the diameter of the wire and l is the length.
Given,
r=15 cm=0.15 m
d=2.7 mm=0.0027 m
i1=48 A
density of copper=8900 kg/m^3
The equilibrium is an unstable one. If the 2nd wire is slightly displaced from the position of equilibrium magnetic force will change and displace the wire further from the equilibrium.