Question

a) When we were examining the Electromagnetic Tab, we saw that a flow of electrons or a current as we say it, creates a magnetic field. What about the converse, can a magnetic field be involved in the creation of a flow of electrons/current? Therefore is it reasonable to suggest that we can create a magnetic field by having a flow of current and this can be used to make more current? Explain how this can occur

Answer 1

Magnetic field can be used to produce current, infact a changing magnetic field can produce current.

A changing magnetic field in a loop causes the flux linked with the loop to change in turn generating a emf in the loop and therefore a current.

For a loop of area A and resistance R.

I =dPhi/dt/R

В. А

I = AcosФ/R .dB /dt

But it isn't reasonable to say that we can create a magnetic field by having a flow of current and this can be used to make more current because the current generated due to change in magnetic field created by increase/decrease in flow of current will be in a direction such that it will counter act the change in magnetic field caused by increase/decrease in current flow.(lenz's law).

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Ф= В. А

I = Acos dB Rd