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2. Spectrum • There are dark parts in the absorption spectrum that represent missing light. What happened to this light that is missing in the absorption line spectrum?1. This light was converted into an atom.2. This light was absorbed by an atom in the gas and then scattered in a random direction.3. This light was converted to gamma rays.4. This light was converted to radio waves.
2. Spectrum • There are dark parts in the absorption spectrum that represent missing light. What happened to this light that is missing in the absorption line spectrum?1. This light was converted into an atom.2. This light was absorbed by an atom in the gas and then scattered in a random direction.3. This light was converted to gamma rays.4. This light was converted to radio waves.
3. Spectrum 2 • Imagine that your are looking at two different spectra of the Sun. Spectrum #1 is obtained using a telescope that is above Earth’s atmosphere (for example, on the Moon). Spectrum #2 is obtained using a telescope located on the surface of Earth. Which spectrum is Spectrum #2 and why. Select the best answer.
3. Spectrum 2 • Imagine that your are looking at two different spectra of the Sun. Spectrum #1 is obtained using a telescope that is above Earth’s atmosphere (for example, on the Moon). Spectrum #2 is obtained using a telescope located on the surface of Earth. Which spectrum is Spectrum #2 and why. Select the best answer.
4. Electromagnetic radiation energy • The equation that tells us how much energy electromagnetic radiation has is E = hc/l, where l is the wavelength. According to this formula, which of the following will have the most energy? 1. A red photon2. A green photon3. A violet photon4. A yellow photon 5. All are the same
4. Electromagnetic radiation energy • The equation that tells us how much energy electromagnetic radiation has is E = hc/l, where l is the wavelength. According to this formula, which of the following will have the most energy? 1. A red photon2. A green photon3. A violet photon4. A yellow photon 5. All are the same
5. Photons and Electromagnetic Radiation • What is the difference between light and electromagnetic radiation?1. A light photon travels faster2. A light photon travels slower3. They are the same thing. What we call visible light is electromagnetic radiation with a frequency that our eyes can detect.4. Electromagnetic radiation can interact with electromagnets while light cannot
5. Photons and Electromagnetic Radiation • What is the difference between light and electromagnetic radiation?1. A light photon travels faster2. A light photon travels slower3. They are the same thing. What we call visible light is electromagnetic radiation with a frequency that our eyes can detect.4. Electromagnetic radiation can interact with electromagnets while light cannot
6. Rutherford's atom • Rutherford shot alpha particles at a thin foil and was able to show that 1. Gold foil has no neutrons2. Gold foil has no electrons3. The atom is generally very empty except for a dense area where protons and neutrons are concentrated.4. The atom is generally very uniform and when you shoot an alpha particle at it, it is very likely to hit a proton an be reflected back.
6. Rutherford's atom • Rutherford shot alpha particles at a thin foil and was able to show that 1. Gold foil has no neutrons2. Gold foil has no electrons3. The atom is generally very empty except for a dense area where protons and neutrons are concentrated.4. The atom is generally very uniform and when you shoot an alpha particle at it, it is very likely to hit a proton an be reflected back.
7. Electromagnetic radiation energy 2 • The equation that tells us how much energy electromagnetic radiation has is E = hc/lamda, where lamda is the wavelength. According to this formula, which of the following will have the LEAST energy?1. A yellow photon2. A green photon3. A violet photon4. A red photon
7. Electromagnetic radiation energy 2 • The equation that tells us how much energy electromagnetic radiation has is E = hc/lamda, where lamda is the wavelength. According to this formula, which of the following will have the LEAST energy?1. A yellow photon2. A green photon3. A violet photon4. A red photon
8. Electromagnetic radiation speed 2 • Which of the following forms of electromagnetic radiation has the highest speed in empty space?1. a gamma ray2. a photon ray3. a radio wave4. a blue photon5. all are the same
8. Electromagnetic radiation speed 2 • Which of the following forms of electromagnetic radiation has the highest speed in empty space?1. a gamma ray2. a photon ray3. a radio wave4. a blue photon5. all are the same
9. Math question 1 • The surface area of the outside of a hollow tube with no caps on the end (like the cardboard tube for a paper towel roll) is equal to 2*pi*radius*height. If the radius of the cylinder doubles, what happens to its surface area (or what happens to the amount of paint you would need to cover its outside). • Note that I have posted some more examples of solving such problems at http://aurora.gmu.edu/astr111/images/Ratios.ppt 1. The surface area doubles2. The surface area triples3. The surface area goes down by one-half4. The surface area goes down by one-quarter
9. Math question 1 • The surface area of the outside of a hollow tube with no caps on the end (like the cardboard tube for a paper towel roll) is equal to 2*pi*radius*height. If the radius of the cylinder doubles, what happens to its surface area (or what happens to the amount of paint you would need to cover its outside). • Note that I have posted some more examples of solving such problems at http://aurora.gmu.edu/astr111/images/Ratios.ppt 1. The surface area doubles2. The surface area triples3. The surface area goes down by one-half4. The surface area goes down by one-quarter A1 =(2*pi*r*h) A2 = 2*pi*(2*r)*r*h=2*(2*pi*r*h)=2*A1
10. Math question 2 (computing your grade) • I try to minimize the amount of math used in this course. Some math is required to understand some concepts, however. And there is some level of math competency that every university graduate should have.Sometimes students ask me how to compute their grade. I think that all college students should be able to do things like compute their grade in a class or compute what would happen to their grade point if they got, for example, a 4.0 or a 1.0 this semester. • If a student got a 90, 80, 70, and 50 on their exams 1-4, respectively, and their quiz average was 90%, what is their overall percentage score? You may need to reference the syllabus at http://aurora.gmu.edu/astr111/index.php/Syllabus#Grading • 1. 82%2. 78%3. 80%4. 81%5. 79%
10. Math question 2 (computing your grade) • I try to minimize the amount of math used in this course. Some math is required to understand some concepts, however. And there is some level of math competency that every university graduate should have.Sometimes students ask me how to compute their grade. I think that all college students should be able to do things like compute their grade in a class or compute what would happen to their grade point if they got, for example, a 4.0 or a 1.0 this semester. • If a student got a 90, 80, 70, and 50 on their exams 1-4, respectively, and their quiz average was 90%, what is their overall percentage score? You may need to reference the syllabus at http://aurora.gmu.edu/astr111/index.php/Syllabus#Grading • 1. 82%2. 78%3. 80%4. 81%5. 79% 90*0.3 + 80*0.3 + 70*0.3 + 90*0.1
11. Overlapping waves 2 • Repeat from Quiz 6.,
12. Photons through a hole • In this diagram, the sun is shown enclosed in an hollow sphere that has a radius of 1 AU. Suppose that you found that 10 photons passed through the 1 meter by 1 meter hole every second. What would you measure if you increased the size of the hole to 2 meters by 2 meters? 1. 10 photons per second would pass through the 2 meter by 2 meter hole.2. 16 photons per second would pass through the 2 meter by 2 meter hole.3. 4 photons per second would pass through the 2 meter by 2 meter hole.4. 40 photons per second would pass through the 2 meter by 2 meter hole.
12. Photons through a hole • In this diagram, the sun is shown enclosed in an hollow sphere that has a radius of 1 AU. Suppose that you found that 10 photons passed through the 1 meter by 1 meter hole every second. What would you measure if you increased the size of the hole to 2 meters by 2 meters? 1. 10 photons per second would pass through the 2 meter by 2 meter hole.2. 16 photons per second would pass through the 2 meter by 2 meter hole.3. 4 photons per second would pass through the 2 meter by 2 meter hole.4. 40 photons per second would pass through the 2 meter by 2 meter hole. (Note quiz had typo – 100 was listed in place of 40)
13. Spectrum 5 • Why do some photons pass right through a cloud of gas while others get absorbed by the gas and then scattered in a random direction?Choose the best answer.1. Every element has a set of special frequencies associated with it. If you hit an element with a photon at one of those special frequencies, it interacts with the element and then later the element sends out an identical photon in a random direction.2. Every element has a set of special frequencies associated with it. If you hit an element with a photon at one of those special frequencies, the photon is reflected back in the direction it came from.3. Every element has a set of special speeds associated with it. If you hit an element with a photon at one of those special speeds, it interacts with the element and then later the element sends out an identical photon in a random direction.
13. Spectrum 5 • Why do some photons pass right through a cloud of gas while others get absorbed by the gas and then scattered in a random direction?Choose the best answer.1. Every element has a set of special frequencies associated with it. If you hit an element with a photon at one of those special frequencies, it interacts with the element and then later the element sends out an identical photon in a random direction. (Technically this is true for element in ground state being excited to its first energy level … in general, emitted photon does not need to be the same as the absorbed photon.)2. Every element has a set of special frequencies associated with it. If you hit an element with a photon at one of those special frequencies, the photon is reflected back in the direction it came from.3. Every element has a set of special speeds associated with it. If you hit an element with a photon at one of those special speeds, it interacts with the element and then later the element sends out an identical photon in a random direction.
