Chapter 4, Review Questions.

Review Questions pgs. 124-125, #1-23 (odd)

1. b 3. c 5. Wien’s law explains that objects of different temperatures emit spectra that peak at different wavelengths. Hotter objects emit shorter wavelengths, thus appearing bluer, whilst colder objects emit longer wavelengths, appearing redder. A star’s surface temperature can be deciphered using this method by seeing its color and surmising the amount of heat it’s giving off. 7. Wien’s law states that the peak of the emission spectrum shifts to shorter wavelengths as the temperature increases, this means that the color changes from red to blue (gradually) as the object gets hotter. The Stefan-Boltzmann law states that the energy radiated per unit surface are increases as the fourth power of the temperature, thus as the temperature goes up, the object gets brighter and brighter, emitting more and more energy. 9. An element is a pure chemical substance consisting of one type of atom distinguished by its atomic number. Hydrogen, carbon, lithium, oxygen, and arsenic are all elements what differentiates them all from each other is that they may be part of different groups of the periodic table and more importantly, their atomic number. 11. It allows us to see the energy state of the atom and to decipher what element it is, if necessary. 13. Because the Doppler shift principle is only applicable in situations in which the object is moving toward or away from the observer, not in any other manner. 15. About 7.5 times. 17. .0029nm/W.Lpeak=T 19. The star is moving away from us, as the wavelength is in the redder area of the electromagnetic spectrum. 21. The method of identifying elements by their spectral line patterns is similar to identifying people by their fingerprints since both of them are characteristics that are unique to an individual. It is almost impossible to find two people with the same pattern of fingerprint, likewise, each different element has a different absorption pattern.