# How to measure the magnetic field/ induced fem in a system

## Homework Statement

Hello, this is like an experiment of engineering.It is called a induction stove. The system consists of a bycicle, where I am going to pedal. This will turn a disk that have 20 small magnets around its circuference. Once the disk starts to turn, it will produce a constant change in the magnetic flux I think. This will produce an induced electric current that will heat a water in a pot.

I can find the energy exerted by the person to pedal the bycicle and the energy to heat the water, since I could measure by using Q=m.Cp ( Tf-to) / time

I also can find the total efficiency of the system by n= energy produced/ energy delivered , where energy produced is the energy due the heat and the energy delivered is the power exerted by the person to pedal. In my sistem I found a efficiency of 30%. So, the 70% is lost due the friciton in the chains and I think I also have losses in the magnets.

Only for curiosity, I would want to know how I can compute the magnetic field, magnetic flux, varation of the magnetic flux, induced fem and current.

## Homework Equations

The equations I know are:

Φ=B.A.cosθ (But I don't know how to find the magnetic field, and I am not sure if that A is referring to the area of the disk) I don't think so, because in a normal excercise, that area is reffering to the area of the spire that is turning around a magnetic field.

Emf = -N ΔΦ/Δt

## The Attempt at a Solution

What I think I can do is to measure the resistance of the pot with a multimeter I think ( not sure how I can measure the resistance of that). Once I know the resistance , i can find the induced current with P=I.R^2 , where P would be almost the same value that Q (power delivered to the water, that I am able to measure easily)
Once I find the Induced curent, I think I could measure the variation of the magnetic flux somehow ( but no sure how)

In my experiment I don't have to measure all those things, it is just for curiosity. I hope someone could say me if it is possible to measure all those variables, or if I need to know some data else.

drvrm
Once I find the Induced curent, I think I could measure the variation of the magnetic flux somehow ( but no sure how)

There are a range of different instruments that can measure magnetic field strength. The gauss meter is a hand-held device that provides a simple way of performing such measurements.

ARPANSA has two different gauss meter models available for hire, which are a Sypris Model 4080 and an EMDEX Snap. Both instruments operate in a similar manner and they are shown in the image above.

• 