Submitted by: Submitted by ChristinaW
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Words: 376
Pages: 2
Category: Science and Technology
Date Submitted: 04/06/2014 11:15 AM
Learning Issues:
1) A spectrum generally describes the variation of a certain physical quantity as a function of wavelength. The term "spectrum" without any further specifications refers to the quantification of the monochromatic intensity as a function of wavelength (the term "spectrum" is also used for other (physical) quantities apart of intensity, but is then always used with a specific prefix. As an example, the strength of a biological reaction (for example erythema) to light with different wavelengths is described by an "action spectrum"). (ref: http://www.light-measurement.com/spectra/)
2) Diffraction Grating Equation: n = d sin( ), In this formula is the angle of emergence (called deviation, D, for the prism) at which a wavelength will be bright, d is the distance between slits (note that d = 1 / N if N, called the grating constant, is the number of lines per unit length) and n is the "order number", a positive integer (n = 1, 2, 3, ...) representing the repetition of the spectrum.
(ref: http://www.physics.smu.edu/~scalise/emmanual/diffraction/lab.html)
3) Approximate wavelength For the various colors
(ref: http://www.livephysics.com/physical-constants/optics-pc/wavelength-colors//0)
Color | Wavelength (nm) |
Red | 780 - 622 |
Red | 780 - 622 |
Orange | 622 - 597 |
Yellow | 597 - 577 |
Green | 577 - 492 |
Blue | 492 - 455 |
Violet | 455 – 390 |
4) Principle emission lines from discharge tubes. All measurements in nano-meters
Colour | Sodium | Mercury | Helium | Cadmium | Neon |
Violet | | 404.6 | 438.8 | | |
| | 407.8 | 443.7 | | |
| | 435.8 | 447.1 | 467.8 | |
Blue | 498.2 | 491.2 | 471.3 | 480.0 | |
| | | 492.2 | | |
Green | 568.2 | 546.7 | 501.6 | 208.6 | 540.0 |
| 568.8 | | 504.8 | | |
Yellow | 589.0 | 577.0 | 587.6 | | 585.2 |
| 589.6 | 579.0 | | | |
Red | 615.4 | | 667.8 | 643.9 | 640.2 |
| 616.0 | | | | |
5) Light Dependent Resistance [LDR] is a...