Two parallel wires are horizontally oriented. the top wire has current of some value i directed to the left, and the bottom wire has current of 2 x i directed to the right. at what point will the magnetic fields cancel out?
a. some point between the two wiresb. some point above the top wirec. some point below the bottom wired. no position cancels the magnetic fields

b. Some point above the top wire

Explanation:

Given:

Given that the current in the top wire travels left and the current in the bottom wire travels right.

The magnitude of magnetic field is given as:

where:

r = radial distance from the center of the wire

magnitude of current in the wire

permeability of free space

Now using Maxwell's right hand thumb rule we determine the direction of the magnetic field around the wire. So, we can deduce that this point will be above the top wire because they are in the opposite direction.

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.