Light: Ray Model

1. Light: Ray Model

2. Suppose you have a small brightly lit bulb, a mask, and a screen. You see a small circle of light on the screen. What would happen to the spot if you moved the bulb straight upward a bit? • The spot would stay where it was. • The spot would move up a bit. • The spot would move down a bit. • The spot would move left a bit. • The spot would move right a bit. • Something else NEXUS/Physics Clicker Questions

3. Suppose you have two lit bulbs, the top one red and the bottom one blue, a mask and a screen, as shown. What would you see on the screen if you held the bulbs one over the other as shown? • One purple circle. • Two circles, one above the other with the top one red, the lower one blue. • Two circles, one above the other with the top one blue, the lower one red. • Something else. NEXUS/Physics Clicker Questions

4. You are sitting in a chair looking at two objects that are suspended from the ceiling. It appears to you that object A is above object B. When you stand up, object A appears to be below object B. Which of the two objects is farther away from you? • Object A • Object B • They are both the same distance. • You can’t tell. It could be either one NEXUS/Physics Clicker Questions

5. I once observed a woman on an airplane at night with a camera. As we flew low over Washington DC she was impressed with the view of the city lights in the dark. She stood back in the aisle and tried to take a picture through the window using her flash. Explain why this is a bad idea and what her pictures are likely to show. NEXUS/Physics Clicker Questions

6. NEXUS/Physics Clicker Questions

7. An observer O, facing a mirror, observes a light source S. Where does O perceive the mirror image of S to be located? • 1 • 2 • 3 • 4 • Some other location • O cannot see S in the mirror when they are as shown. NEXUS/Physics Clicker Questions

8. I have a small mirror – about 8 inches high – hanging on my wall. When I’m standing right in front of it, I can only see my head. Can I see all of myself at once by moving far back enough? • Yes • No • I can if I … NEXUS/Physics Clicker Questions

9. How large a mirror do you need in order to see your whole body? • You can see yourself in any size mirror if you go back far enough. • About half your size. • As big as you are. • Some other answer. NEXUS/Physics Clicker Questions

10. What does a flat mirror do to the image? • Flips it left to right. • Flips it upside down. • Does both. • Does something else. NEXUS/Physics Clicker Questions

11. What will a real image look like if there is no screen? • Nothing. You won’t be able to see the image without the screen. • You will still see the image, but it will appear to be floating in front of the mirror. • You will still see the image, but it will appear to be on the mirror. • You will still see the image, but it will appear to be behind the mirror like it is with a flat mirror. NEXUS/Physics Clicker Questions

12. If we get very far away from the back of a curved mirror of radius R, where does the image appear to go?Answer using ray analysis and the mirror equation. • 1. R behind the mirror • 2. R/2 behind the mirror • 3. at the mirror (just behind it) • 4. very far behind the mirror NEXUS/Physics Clicker Questions

13. A ray of light is moving from one medium (blue) into another (yellow). Which of the outgoing rays is the most plausible if A.both media have the same n?B. nblue > nyellow?C. nblue < nyellow? NEXUS/Physics Clicker Questions

14. What happens if you put a screen at the image distance for a real image? • You won’t be able to see the image from anywhere. • You will be able to see the image from anywhere. • You will be able to see the image on the screen if you are on the same side of the screen as the lens • You will be able to see the image only if you are lined up to see the object through the lens. NEXUS/Physics Clicker Questions

15. What happens if you put a screen at the image distance for a virtual image? • You won’t be able to see the image from anywhere. • You will be able to see the image from anywhere. • You will be able to see the image on the screen if you are on the same side of the screen as the lens • You will be able to see the image only if you are lined up to see the object through the lens. NEXUS/Physics Clicker Questions

16. What happens to the image if the object moves a little closer to the lens? • The image will also get closer to the screen. • The image will stay where it was before. • The image will get farther from the lens. • The image will move to the left side of the lens. • You can’t tell what will happen without more information. NEXUS/Physics Clicker Questions

17. What happens to the image if the object moves a lot closer to the lens (inside the X)? • The image will also get closer to the screen. • The image will stay where it was before. • The image will get farther from the lens. • The image will move to the left side of the lens. • You can’t tell what will happen without more information. NEXUS/Physics Clicker Questions

18. What happens on the screen if you block part of the lens with a cardboard? • It will block part of the image on the screen. • It will make the image dimmer but you will see the whole image. • Something else. • It depends on where you put the block. NEXUS/Physics Clicker Questions

19. What happens on the screen if you block part of the lens with a cardboard as shown? • It will block part of the image on the screen. • It will make the image dimmer but you will see the whole image. • Something else. • It depends on where you put the block. NEXUS/Physics Clicker Questions

20. What happens on the screen if you block part of the lens with a cardboard as shown? • It will block part of the image on the screen. • It will make the image dimmer but you will see the whole image. • Something else. • It depends on where you put the block. NEXUS/Physics Clicker Questions