Faraday Law Lab PDF

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Lab on faraday's law...

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Samuel King PHYS2064 18 July 2018

Faraday’s Law Lab : 18 July 2018

IntroductionIn this lab I observed the magnetic field strength around a solenoid that carried a current and thus produced a magnetic field. We calculated the emf induced in a small coil placed within the magnetic field of the solenoid under varying conditions. This lab was preformed in joint effort with Daniel Shultz, a classmate, and we both wrote different parts of the lab report and were able to discuss what we learned together.

Materials- TI-84 Plus Calculator KET Virtual Electrostatics Lab Lab Notebook Pen

ProcedureTo start off the lab, we calculated a theoretical value for the strength of the magnetic field around the Solenoid that we set up and then took an experimental measurement and calculated the percentage of error. Using the equation ���� = ����and a value of 6v for the current, we used other values for the number of turns and length of the solenoid and got these values: Theoretical Value 0.0253 Teslas

Experimental Value 0.0249 Teslas

Percent Error 1.58%

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Next we shifted our focus to the changing magnetic flux through a coil of wire. We achieved this by moving a smaller coil (pickup) through the magnetic field of the solenoid. We moved the pickup around side-to-side through the magnetic field. Then using the Hall Probe to get a more precise point measurement, we precisely measured the field strength throughout the entire field in a couple of different manners. We moved the probe steadily through the solenoid first, and then came back and made 5 different point measurements in and around the solenoid. At 50v we took the following measurements: Far left 12.57 Guass 0.001257 Teslas

Left of solenoid 215.02 Guass 0.021502 Teslas

Center 415.71 Gauss 0.041571 Teslas

Right of solenoid 224.31 Guass 0.022431 Telsas

Far right 12.42 Gauss 0.001242 Teslas

*The graph of plotted points of field strength is in a screenshot below. Using the equations � =�A and ��� =−� �� / �� =−� � �� � � /�tt on a v i g a t e ,wet h e n mo v e do nt od i s c o v e rh o wt h ed e n s i t yo ffie l dl i n e sc a ni mp a c tfie l ds t r e n g t ha swe l l .Todot h i s , we“ j i g g l e d ”t hep i c k upb a c ka n df o r t hi nd i ffe r e n tp r o x i mi t i e st ot hes o l e n oi da n dc r e a t e dal i n e g r a p ht h a th e l p e dt oi n d i c a t et h a tac h a n g ei nfie l ds t r e n g t ho c c u r r e da sac h a n g ei nt h er e l a t i o nt o a r e a so fmo r ea n dl e s sd e n s efie l dl i n e s .An o t h e rwa yt ome a s ur efie l ds t r e n g t hi sb yc h a n g i n gt h e c u r r e n t ,wh i c hwed i dn e x t .Wec h a n g e dt hec u r r e ntf r omn e g a t i v et op os i t i v ea nda l t e r e dt h e a mo u nte a c ht i mes p o r a d i c a l l ys ot ha twec o u l ds e et hep r o gr a mp l o tt hec h a n g e si ns t r e n gt h . Fi na l l y ,weu s e das i n ef u n c t i o no ft heg r a p h i n gpr o g r a mt os i mu l a t et h es t r e n gt hu n d e ra n a l t e r na t i n gc u r r e n t .I non es e c o n di n t e r v a l s ,wet r a c k e dt h ec u r r e n tt oh o p e f u l l yd e t e r mi n et h e s l o p eo ft h eg r a p h .Th e nwes wi t c h e dt oat r i a n g u l a rwa v eont h ef u nc t i o ng e n e r a t o ri no r d e rt o t r a c ki tmo r ee a s i l y .Wee nd e db yc a l c ul a t i n gt h ema g n e t i cfie l da tt h ec e n t e ro ft hes o l e n oi d

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wh i c hwa s1 . 7 3 7x1 0 ^ 4Te s l a sa n dt h e nc a l c ul a t e dt h ee mfa n dc o mp a r e di tt ot h eme a s u r e d e mf : Me a s u r e de mf 3 . 0 7mV

Data-

Th e o r e t i c a le mf 1 1 4. 5 4mV

% Er r o r 9 7 . 3 2 %

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ObservationsAs I moved the short pickup through the solenoid it sensed a larger, stronger field as I got closer and got exponentially stronger to the point that it was strongest in the middle.

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Flux density relies on the magnetic flux (flow) through a coil and thus the density or closeness of magnetic field lines. No matter where the pickup was in the solenoid, it always had a steady 0 emf when it was still. Only once it moved did it change and the greatest readings came from either end of the solenoid. I also noticed that when using the Hall probe, sine waves were in sync when using the alternating current, but once I switched to the pickup, they became out of sync.

Results- shown in tables in procedure and in the pictures in data. ConclusionThe purpose of this experiment was to measure and witness differing magnetic field strengths around a solenoid in a plane and to calculate different emfs surrounding it. The measurements and calculations were achieved and a deeper understanding of how they all work together was arrived at. However, there was quite a bit of error on the last emf calculation. I believe that was because of a lack of understanding of units and the exact directions. The ability to make precise measurements was not much of an issue because most of the time there was some sort of way to know if you were right based off of a number produced by starting the simulation. Another caveat was that it was very hard to define where the back side of the solenoid was and exactly how long it was....