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Exercise 1: Building and Calibrating a Spectroscope Questions Please complete th

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Question

Exercise 1: Building and Calibrating a Spectroscope

Questions

Please complete the questions as you work on the exercise. (6pts)

Hold the grating several inches from your face, at an angle. Look at the grating that you will be using. Record what details you see at the grating surface.

Hold the diffraction grating up to your eye and look through it. Record what you see. Be specific.

Before mounting the diffraction grating, look through the opening that you made for your grating. Record what you see across the back of your spectroscope.

After mounting the diffraction grating, look through your spectroscope and record what you see across the back of your spectroscope. Be specific.

Starting at the light inlet slit and going outward, what colors do you see in the spectrum? List them all.

When you view the spectrum, you should be able to see a spectral image to the right and left of the light inlet slit. How are the spectral images the same? How are they different? Record your findings.

Try narrowing and widening the light inlet slit. How does this affect the spectra that appear? Compare the shape, thickness, and resolution of the spectral lines before and after narrowing the slit. Record your findings.

Write up to five sentences describing how a spectroscope works. Make certain to mention things like the light inlet slit, diffraction grating, light, spectrum, etc.

Exercise 2: Using the Spectroscope

Data Table 1. Light Sources. (6pts)

Light Source

Continuous or Line

Spectra Drawing

Fluorescent

Incandescent

Street Light

Car Headlight

Additional:

___________

Questions

Describe the similarities and differences between the spectra of incandescent light and fluorescent light. Use your results in Data Table 1 to explain your answer.

Light Source

Continuous or Line

Spectra Drawing

Fluorescent

Incandescent

Street Light

Car Headlight

Additional:

___________

Explanation / Answer

Spectra of incandescent light - An incandescent filament is just a hot body, and gives you a continuous spectrum more similar to that which is produced by the sun. Incandescent light spectra is variable depending on the filament used, so it is not just red. The colors will look smeared together rather than banded. You may get a better spectrum by letting the light bounce off a white piece of paper. When viewing a light directly, the brightness is somewhat uneven.

Spectra of Fluorescent light - A fluorescent source works by producing high-energy states (sometimes called "excited states") of atoms, which emit energy as light of definite wavelengths. This is because there are only definite energy levels that electrons can fit into around an atom.

If you get the chance, look at a fluorescent light through a prism or a diffraction grating. You will see separated colours with gaps in between them.