physic lab report

Microwaves SMU Physics 142L – 172L

Microwaves

Purpose:

In this lab we will observe several properties of microwaves—properties shared with visible light and other waves.

Introduction:

Microwaves occupy the area of the electromagnetic spectrum below Infrared and Visible light. Unlike visible light, microwaves cannot be seen, but are used everyday in radio and television broadcasts, cordless and cell phones, radar, microwave ovens, etc. The microwave transmitters we will be using in this lab, however, emit less than 1/10,000th the power of the average microwave oven, so you can not fry anything (including yourself) accidentally or otherwise.

Procedure:

A microwave accessories set and instructions has been provided. Please return the accessories kit at the end of the lab period. Follow the instructions to complete:

Experiment 2: Polarization, Experiment 3: Reflection, Experiment 4: Standing waves, and Experiment 5: Index of refraction.

Analysis:

Experiment 2 Polarization: Determine the polarization of the microwave transmitter. Is the reduction in transmitted power consistent with the formula for polarizing filters?

With the slats up and down, the transmitter goes from 100 to 0. When the filter has its slats horizontal, the transmitter stays at 100 from 100. When the filter is set at a 45 degree angle like \\\\ it goes from 100 to 42. When the filter is set at a 45 angle like ///// it goes from 100 to 62.

Experiment 3 Reflection: What is the relationship between the angle of incidence and the angle of reflection? Is this consistent with your expectations?

Experiment 4 Standing Waves: From your data on the distance between peaks (resonance) on the standing wave, determine the wavelength and frequency of the microwave signal. How does it compare to the frequency published by the manufacturer? (Blue transmitter: 10.525 GHZ; Grey transmitter: 9.83GHZ)

Experiment 5 Refraction: Calculate the index of refraction for the materials provided. How do your values compare to the results obtained by Saint Martin’s physics students over the past few years? (Sand: 1.75; Polyethylene: 1.4)

Lab Evaluation:

Please provide feedback on the following areas, comparing this lab to your previous labs: How much fun you had completing this lab; How well the lab prep period explained this lab; The amount of work required compared to the time allotted; Your understanding of this lab; The difficulty of this lab; How well this lab tied in with the lecture. Please assign each of the listed categories with a value from 1-5, with 5 being the best, 1 the worst. Comments supporting or elaborating on your assessment can also be very helpful in improving the future labs.

Date Last Modified March 25, 2011 Page Number 4