# Magnetism and Induction - How the voltage ratio relates to magnetic field strength equations

## Re: Magnetism and Induction - How the voltage ratio relates to magnetic field strength equations

Thank you for clearing that up!

**lferrie**- Posts : 10

Join date : 2013-01-09

## Re: Magnetism and Induction - How the voltage ratio relates to magnetic field strength equations

the magnetic field is a function of distance, so it will get weaker the further out you go. Since the magnetic field produces a flux of magnetic field lines through the field coil, and the magnetic flux is proportional to the induced voltage (Faradays law), the magnetic field is therefore proportional to the induced voltage. We then use the ratio of voltage and magnetic field to compare since the constants or proportionality will cancel out and the curves should be the same.

A similar argument can be used for the angle dependence. The magnetic flux is the dot product between the magnetic field and the area vector of the field coil. So, the magnetic flux is proportional to cos(theta). From Faradays law the induced voltage is proportional to the magnetic flux, therefore the induced voltage is proportional to cos(theta). Once again we use the ratios to cancel out the constants of proportionality.

A similar argument can be used for the angle dependence. The magnetic flux is the dot product between the magnetic field and the area vector of the field coil. So, the magnetic flux is proportional to cos(theta). From Faradays law the induced voltage is proportional to the magnetic flux, therefore the induced voltage is proportional to cos(theta). Once again we use the ratios to cancel out the constants of proportionality.

**MattChequers**- Posts : 47

Join date : 2013-02-25

## Magnetism and Induction - How the voltage ratio relates to magnetic field strength equations

I'm having a hard time understanding how the voltage ratio's for distance and for the angle relate to the theoretical magnetic field strength curves b(x) and cos(θ) because why should the voltage ratio be equal to the magnetic field strength?

**lferrie**- Posts : 10

Join date : 2013-01-09

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