Answer to Question #97480 in Electricity and Magnetism for Abru

Question

Number of winds Magnetic Field (mT)

0=-0.000109173,

3=0.105413911,

6=0.280796205,

9=0.491070432,

12=0.638107704,

15=0.799167543,

18=0.799167543,

21=1.166024878.

1. What is the relationship between the number of winds and magnetic field strength?

2. According to your graph, what would the magnetic field strength reading be for 10 winds? For 30 winds? Explain.

3. Write a discussion and conclusion about this experiment. Summarise the results. Include some thoughts on the underlying physics involved and sources of errors that may have been observed.

Answer 1

1. Put this data to any processing software and plot it, add a best fit line:

The equation is:

$$B(N)=(0.0529N-0.0206)\text{ mT}.$$

0.0206 mT is some initial magnetic field.

2. For 10 winds it is about 0.5 mT according to the graph, we just look at the graph, 10 winds, and go upward till the curve. Then we go to the left to see the magnitude of the magnetic field. Use our expression for 10 and 30 turns:

$$B(10)=(0.0529\cdot10-0.0206)=0.5084\text{ mT},\\B(30)=(0.0529\cdot30-0.0206)=1.5664\text{ mT}.$$

3. To answer about the experiment, we need to know the procedure itself and how the values were obtained, that is, for instance, were the values for the magnetic field measured once or it is an average? What was the sensitivity of the device used for measuring the field? This information would help to determine which error contributed the most, whether it is a random or systematic error.