MAPUA INSTITUTE OF TECHNOLOGYDepartment of Physics

E401: MAGNETIC FIELD ANDMAGNETIC FORCE

REYES, Mary Grace G.2013108107 BSCpE-2 Group 5PHY13L-B5

Analysis /25Conclusion /25Presentation /10

TOTAL

Engr. Ericson D. DimaunahanInstructorJuly 31, 2015ANALYSISThe experiment has two parts; the first part of the experiment is about magnetic fields of bar magnets, four set ups where prepared. The first and second set-ups make use of two bar magnets, it is set such that the like poles of a bar magnet was facing each other and for another set-up, unlike poles were facing each other. For the third and fourth set-ups two U magnets were used with their unlike poles facing each other, an iron ring was added for the fourth set-up. A picture of how the magnetic flux behaved through each set up was shown in figure 1& 2. One of the difficulty that we encountered in performing this experiment was the arrangement of iron filings in the bond paper wasnt that clear and it is hard to determine whether the direction of its magnetic flux was away or towards the magnet. Figure 2. Two bar magnetsFigure 1. Two U-magnets

In the second part of the experiment we had analysed about magnetic force on current-carrying conductor. We observed the effect of magnetic field, current, length of current loop, and orientation of coil to the magnetic force. Materials such as power supply, current balance, accessories, digital balance, and iron stand were used to perform the experiment about magnetic force on a Current-Carrying conductor. The set-up was shown in figure 3. Using a digital balance we measured the increase in mass of the magnet assembly because as what is said in the manual it is actually the magnetic force on the current loop. The magnetic force that the digital balance will show us is in grams, to convert that in Newton a formula was used and it was shown in the sample computation. To discern more about the relationship of the magnetic force and magnetic field five trials were made, in each trial the number of magnets placed were increased, and as the increase happened there is also an increase in magnetic force. By incrementing the current by 0.5A the magnetic force also increments per trial. To observe the relationship of magnetic force and length of current loop, different current loop were used every trial, for each current loop there is different length and it is observed that as the length increases, the magnetic force also increases. Lastly, we had determined the relationship of the orientation of coil to the magnetic force; we had tried different angles clockwise and counter clockwise. If the angle is negative or measured clockwise, the magnetic force will also be negative but the magnitude would be the same. As we increment the angle the magnitude of the magnetic force in newton also increments. A graph was shown in figure 4 in order to easily identify the relationships between the quantities.Figure 3. Set-up for Part B

Figure 4. Graph of the magnetic force

Sample Computation

Part 2a. Computing Magnetic force in Newton from gramsMagnetic Force = 0.6 g

0.6g x x (9.8 m/s2) = 5.88x10-3 N

Magnetic Force= 5.88x10-3

CONCLUSIONAfter the experiment was done we have been familiarized with the behaviour of magnetic fields around the poles of permanent magnets, figured out the magnetic forces magnitude on a current-carrying wire, discerned about the characteristics of the relationships between magnetic field and other quantities like magnetic force, length, current, and orientation of current carrying wire. It was shown in the arrangement of iron filings in the experiment that like poles of bar magnets will repel while unlike poles of a bar magnet will attract, this agrees to the properties of magnets that was discussed in our lecture class. Iron ring will affect the distribution of magnetic flux; some of it will be attracted to the iron filing instead of being attracted to just the other U-magnet alone. The magnetic force on current- carrying conductor can be determined by getting the summation of magnetic force on each of the individual charges that make this current. From our experiment we had discovered that the number of magnets, current, length of current loop, and orientation of coil are directly proportional to the magnetic force because as we increment the value of those, the magnetic force also increments. The graph of values obtained from the experiment was shown above also proves that they were directly proportional. Our results were parallel to the formula derived from the theory about the magnetic force of a wire exposed to a magnetic field which is F= ILBsin.