PASCO WA-9316A Complete Microwave Optics System - Manual (Page 35)

Experiment Guide Teacher’s Guide
35
Method B
Average wavelength: 2.81 cm
Frequency: 1.07 x 10
10
Hz
Answers to Questions
The value obtained by the first method was 5.6% off, and the second was 1.5% off. If it is possible to take more data points on
the second method, you may get better results.
Experiment 4: Refraction Through a Prism
Notes on the Procedure
1. The empty foam prism absorbs the radiation by a very slight amount.
  = 7° (± 1°)
4  
1
= 22°

2
= 29°
5. Our experimental value was: n
1
= 1.3 ± 0.05
6. Our experimental value was: n
1
= 1.3 ± 0.05
Answers to Questions
1. This assumption is valid. According to Snell’s law, if the angle of incidence is zero, the angle of refraction is zero also.
2. The index for a solid styrene prism would be higher, due to the greater “optical” density of the solid material.
General Notes
The prism mold may be filled with other materials as well. We used water for one such test. The water absorbs most of the
microwave energy (this is how a microwave oven works) but enough gets through that it may be measured on the most sensi-
tive scale of the receiver. We found that n = 1.4 ± 0.05.
Experiment 5: Polarization
Notes on the Procedure
2.
Antinodes Distance (cm) Wavelength (cm)
5 7.1 2.84
10 14.1 2.82
15 20.0 2.67
20 27.5 2.89