Electromagnetic Radiation

The objective of the experiment is to observe the behaviors of antennas and how they work.

Procedure:

See Physics 4C class handout titled "Electromagnetic Radiation Lab."

 

Data and Observations

Distance (m)	# Peak-to-Peak Divisions	Vertical Scale (mV)	Peak-to-Peak Amplitude
0	7	20	140
0.05	4.2	10	42
0.1	5.4	5	27
0.15	4	5	20
0.2	3	5	15
0.25	2.8	5	14
0.3	2.2	5	11
0.35	2	5	10
0.4	1.9	5	9.5
0.45	1.8	5	9
0.5	1.6	5	8
0.55	1.5	5	7.5

 This data graph seems to have an inverse relationship between amplitude and distance, 1/r.

Analysis

1/r

1/r^2

1/r^3

It seems that out of 1/r^n, 1/r^3 has the best fit. This makes since far electromagnetic fields have a 1/r^3 dependency. 1/r^2 is for near fields and point charges are 1/r.

Error Analysis and Conclusion

This is an experiment of a complicated nature, so some simplifications were used. For example, our antenna is nothing more than a piece of copper wire, so it won't work ideally. In addition, the distances were measured using only a ruler, so the values may be off by ± 1 cm. These are probably why no curve fits the data perfectly.