We are doing an experiment in my physics lab that involves trying to find the horizontal component of the Earth's magnetic field. Here is a little explanation of what is going on: We have a bar magnet that is placed inbetween a set of Helmholtz coils (125 of them coiled) and we place a certain current (i) on the coils. We then see that the bar magnet begins to try to align itself with the magnetic field, but it will have an angular momentum that will cause it to continue turning past the direction of the magnetic field creating oscillations. Our instructor told us to count 25 oscillations and find the time it takes for 25 to occur. From that we can then find the period of oscillations(T) from each current. Then we can find 1/T^2 from this. We then plot a graph with current(i) on the x-axis and 1/T^2 on the y axis and we find its a straight linear line. Our Instructor stated that the y-intercept will be our b and our slope will be S. From the equation given in our packet which is: (32pN x 10^-7/r x radical 125) x b/S. I know that N is the number of coils, r is the radius(9.6cm), b is the y-intercept, and S is the slope. However, from my graph, my equation for the line of best fit was y=0.967x - 0.3068. plugging this in (32p(125) x 10^-7/9.6cmx radical 125) x (.3068/.967) I get 4.643x10^-4. Putting this into gauss by multiplying times (10^4) i get 4.64 which i know is far off since NASA says its around 0.2-0.5 gauss average around Earth. I would really appreciate the help for what im doing wrong.
We are doing an experiment in my physics lab that involves trying to find the horizontal component of the Earth's magnetic field. Here is a little explanation of what is going on: We have a bar magnet that is placed inbetween a set of Helmholtz coils (125 of them coiled) and we place a certain current (i) on the coils. We then see that the bar magnet begins to try to align itself with the magnetic field, but it will have an angular momentum that will cause it to continue turning past the direction of the magnetic field creating oscillations. Our instructor told us to count 25 oscillations and find the time it takes for 25 to occur. From that we can then find the period of oscillations(T) from each current. Then we can find 1/T^2 from this. We then plot a graph with current(i) on the x-axis and 1/T^2 on the y axis and we find its a straight linear line. Our Instructor stated that the y-intercept will be our b and our slope will be S. From the equation given in our packet which is: (32pN x 10^-7/r x radical 125) x b/S. I know that N is the number of coils, r is the radius(9.6cm), b is the y-intercept, and S is the slope. However, from my graph, my equation for the line of best fit was y=0.967x - 0.3068. plugging this in (32p(125) x 10^-7/9.6cmx radical 125) x (.3068/.967) I get 4.643x10^-4. Putting this into gauss by multiplying times (10^4) i get 4.64 which i know is far off since NASA says its around 0.2-0.5 gauss average around Earth. I would really appreciate the help for what im doing wrong.
