E305 Equipotential LInes

Mapúa Institute of Technology Department of Physics

Experiment 305 ELECTRIC FIELDS AND EQUIPOTENTIAL LINES

Name: Saccuan, April Jem H. Program/Year: CpE/2 Course Code/Section: PHY12L/A1 Student No.: 2012100116 Group No.: 5 Seat No.: 502 Date of Performance: February 11, 2014 Date of Submission: February 18, 2014

Prof. Bobby Manlapig Instructor

GRADE

QUESTIONS AND PROBLEMS 1. Is it possible for equipotential lines to intersect each other? Justify your answer. Yes, it is possible for equipotential lines to intersect each other if and only if the two charges have the same charge (positive-positive or negative-negative), same value of the potential as each other, and they are emerging from or converging to the same singularity. 2. From the electric field pattern that you obtained, what is the relationship between the spacing of the field lines and the electric field magnitude? It is not quite seen in the pattern drawn but more likely, the closer the field lines are to each other, the stronger the electric field magnitude will be. By the equation and graph it is said that the electric force is also inversely proportional to the square of the distance of charges with each other. 3. If an electron is at the midpoint of the line connecting two equal but opposite charges in a direction perpendicular to this line, does the charge experience zero electric force due to the two charges? If not is there a point along the line connecting the charges where the electron will experience a zero electric force? Where is this point located? The charge does not experience zero electric force because for the point midway between the forces acting on the electron are in same line but also in the same direction so they will add. The force will be zero only at infinity because between the charge forces will add but beyond forces will oppose but they would never be equal in magnitude. 4. Sketch the electric field between two positive charges of equal magnitude.

MAP UA INSTITUTE OF TECHNOLOGY DEPARTMENT OF PHYSICS EXPERIMENT 305 : ELECTRIC FIELDS AND EQUIPOTENTIAL LINES Name Program/Year Subject/Section

Saccuan, April Jem H. CpE/2 PHY12L/A1

Group No. Seat No. Date

5 502 02/11/14

DATA and OBSERVATIONS A. Dipoles of Unlike Charges Multimeter Reading 3.23 Volts

3.27 Volts

3.32 Volts

3.38 Volts

3.46 Volts

Coordinates, (x,y) 9 9.5 10 12 8 10 11 12 7 9 10 12 6 7 9 12 5 7 9 12

0 1 2 3 0 3 3.5 4 0 4 5 5.5 0 3 5.5 7 0 6 8 9

MAP UA INSTITUTE OF TECHNOLOGY DEPARTMENT OF PHYSICS EXPERIMENT 305 : ELECTRIC FIELDS AND EQUIPOTENTIAL LINES Name Program/Year Subject/Section

Saccuan, April Jem H. CpE/2 PHY12L/A1

Group No. Seat No. Date

5 502 02/11/14

DATA and OBSERVATIONS B. Point Source and Guard Ring Multimeter Reading

Coordinates, (x, y)

6.43 Volts

6.36 Volts

6.29 Volts

6.23 Volts

6.21 Volts

6 3 5 0 5 4 2 0 4 3 2 0 3 2 1 0 2 1.5 1 0

0 5 3 6 0 2 4 5 0 2 3 4 0 2 2.5 3 0 1 1.5 2

Approved by:

Prof. Bobby Manlapig instructor

02/11/14 date

ANALYSIS 1. Why is the voltage reading along an equipotential line zero? The digital voltmeter measures the potential difference between the point on the paper where the probe is held and the conductor connected to the other lead of the voltmeter. Voltage is a potential difference. Since we read along an equipotential line or a line with equal potential, then getting its difference will yield no difference, as well as, voltage. 2. At what point is the voltage reading greatest? What is the significance of this? The greatest voltage reading would be if the difference between the lines of equipotential is greatest. A positive test charge would be at high electric potential when held close to a positive source charge. Hence, decreasing the distance from the point source, the voltage increases. Knowing this relationship would be of great reminder that when a test charge is being made which is very far from the point source, a high voltage was being made and high voltages should be taken cautioned of.

3. Describe the electric field inside the guard ring. Plotting the points with equal potential on a guard ring and using origin as the point source, circular paths are produced. This means that as the circular silver lining was made, the electric lines are trapped inside the ring because silver is a conductor and thus conduct electricity. The same in the first experiment, conversely, increasing the distance from the point source the voltage decreases.

CONCLUSION In this experiment, we studied the nature of electric fields by mapping the equipotential lines and then drawing in the electric lines of force or electric field lines which are always perpendicular to each other. An electric field is an area where electric force is present while equipotential lines are lines with equal potential. For experiment 1, plotting the points with equal potentials produce a parabolic figure and then the field lines are drawn intersecting the potential lines perpendicularly. For experiment 2, we produce circular potential lines and so the electric field lines are all radii of the guard circle and the other circles since we produce concentric potential lines. Performing this experiment, it is concluded that equipotential lines are proportional in strength with respect to the distances from the point source. Finally, voltage is indirectly proportional to the distance from the point source.