Exam 3 Physics! 1 more to go!! ALMOST THERE!!!

Correlation between energy and wavelength as follows:

700 nm = 1.77 eV 600 nm = 2.07 eV 550 nm = 2.25 eV 500 nm = 2.48 eV 400 nm = 3.1 eV

19. What type of waves are light waves (circle one answer) ? a. Transverse b. Longitudinal c. d. Triangular e. none listed to the left

a. Transverse

28.Violet light has a shorter wavelength than red light. Which has the greater frequency (circle one answer) ? a. Violet light b. red light c. neither

a. Violet light

20. Which effect or experiment best shows the wave nature of light via interference of light (circle one answer) ? a. Young's double-slit experiments b. total iCircular nternal reflection. c. the refraction of light d. the photoelectric effect

a. Young's double-slit experiments

37. Coherent light is most likely to come from (circle one answer) ? a. a laser b. an incandescent bulb c. a neon light d. a stop light e. a street light

a. a laser

17. Animal life in the sea has evolved so as to avoid detection by predators. It is important that like that strikes them is not reflected so its predators can not see them clearly. Many of these animals are black. Another dominant color is (circle one answer) ? a. red b. orange c. yellow d. magenta e. blue

a. red

11. Which color of light is least likely to cause photoelectrons to be produced (circle one answer) ? a. red light b. yellow light c. orange light d. violet light

a. red light

27. As a solid object is heated to higher temperatures it emits more light at (circle one answer) ? a. shorter wavelengths as the temperature rises b. Longer wavelengths as the temperature rises c. the same wavelength because the light depends on the substance only

a. shorter wavelengths as the temperature rises

33. Refraction of the light from the sun causes (circle one answer) ? a. Days to be shorter b. Days to be longer c. sunsets to be red d. Has no effect on the appearance of the sun

b. Days to be longer

30.. Ozone in the upper atmosphere is important because it (circle one answer) ? a. Absorbs infrared light b. absorbs ultraviolet light c. absorbs visible light d. makes air fresher

b. absorbs ultraviolet light

3. Quantum uncertainties in the measurements of physical properties are most important when measuring properties of which of the following objects (circle one answer) ? a. the earth b. an electron c. the sun d. a baseball e. no objects listed to the left

b. an electron

34. Our brain can adjust the focal length of the lens of our eye. This helps us (circle one answer) ? a. See color better b. focus the image of an object on the retina better c. see better at night d. adjust for bright and dim light better

b. focus the image of an object on the retina better

26. . The cones in our eyes (circle one answer)? a. provide vision in low light b. provide color vision and detail. c. focus the light on the retina d. refract the light

b. provide color vision and detail.

18. . A ray of light travels from a material of higher index of refraction to one of lower index of refraction at an angle to the normal greater than the critical angle. The ray of light will be (circle one answer)? a. bent toward the normal b. reflected at an angle equal the incident angle c. bent away from the normal d. travel straight though the interface

b. reflected at an angle equal the incident angle

10. Which effect or experiment best shows the particle nature of light (circle one answer) ? a. Young's double-slit experiment b. total internal reflection. c the photoelectric effect d. the refraction of light

c the photoelectric effect

13. At what wavelength (in nanometers) does our color visual acuity peak (circle one answer) ? a. 250 b. 350 c. 550 d. 750

c. 550

23. Due to the effects of refraction of light, a bird flying directly above an observer under water will have an apparent height above the water that is (circle one answer) ? a. less than the actual height b the same as the actual height. c. greater than the actual height

c. greater than the actual height

15. "Alien" is a creature from an alien solar system whose visual acuity peaks in the iultraviolet. Its "sun" is likely to be (circle one answer) ? a. the same temperature as our sun b. cooler than our sun c. hotter than our sun

c. hotter than our sun

31. You are at a swimming pool (above the water) looking at a sign that is half in the water and half out. The letters on the sign are all printed the same height. The letters under the water will appear to be (circle one answer).? a. the same height as those above the water b. greater height than those above the water c. lesser height than those above the water

c. lesser height than those above the water

8. An object is placed at a position inside the focal length of a converging lens. The image is (circle one answer)? a. Demagnified, inverted and virtual b. magnified, inverted and real c. magnified, upright and virtual

c. magnified, upright and virtual

5. An object is placed in front of a concave mirror at a distance further from the mirror than the focal length . The image is (circle one answer)? a. real and upright b. virtual and upright c. real and inverted d. virtual and inverted

c. real and inverted

35. Why is the sky blue (circle one answer) ? a. absorption of red light b. reflection of blue light from the ocean c. scattering of blue light by molecules in the air

c. scattering of blue light by molecules in the air

36. Why is the sunset red (circle one answer) ? a. absorption of light of higher frequency than red (for example, blue light) b. scattering of light of lower frequency than red (for example, infrared light) c. scattering of light of higher frequency than red (for example, blue light)

c. scattering of light of higher frequency than red (for example, blue light)

6. What part of the rainbow appears violet (circle one answer).? a. The top b. the middle c. the bottom d. there is no violet in the rainbow

c. the bottom

24.. If white light is passed through a prism which color light is dispersed (bent) the most (circle one answer) ? a. red b. green c. violet d. blue e. orange f. yellow

c. violet

9. . A single slit diffraction pattern is projected on an image screen perpendicular to the light rays coming through the slit. The wavelength of the light is 600 x 10-9 m . The second dark fringe is located on the image screen at an angle equal to 30° from the line from the slit to the center of the central bright fringe. The width W of the slit is (circle one answer) ? a. 600 x 10-9m b. 1200 x 10-9m c. 300 x 10-9m d. 2400 x 10-9m e. 1800 x 10-9m

d. 2400 x 10-9m

32. A metal has a work function of 2.0 eV. To produce a photoelectron incoming light must have energy (circle one answer) a. Exactly equal to 2.0 eV b. Less than 2.0 eV c. Depends on the intensity of light, not energy d. Exactly equal to or greater than 2.0 eV

d. Exactly equal to or greater than 2.0 eV

7. When we see a rainbow where is the sun relative to us? a. in front of us b. to the left of us c. to the right of us d. behind us

d. behind us

12.. A properly cut diamond will appear to sparkle more than glass because it (circle one answer) ? a. reflects light better than glass b. absorbs light better than glass c. scatters light better than glass d. has more total internal reflections due to its higher index of refraction

d. has more total internal reflections due to its higher index of refraction

4. It is difficult to see down a wet road at night because (circle one answer) ? : a. Water absorbs light. b. light is diffusely reflected off the surface of the water c. water amplifies light d. light is specularly reflected from the surface of the water

d. light is specularly reflected from the surface of the water

21. You buy a pair of polarized sunglasses to avoid glare. In what direction should the glasses be polarized (circle one answer) ? a. horizontal b. circular c. elliptical d. vertical

d. vertical

1. Among the following colors, which color light results from the largest energy transition in an atom (circle one answer) ? a. green b. blue c. red d. violet e. orange

d. violet

39.. A metal has a work function of 2.48 eV = 4.0 x 10-19J. To produce a photoelectron with zero energy incoming light must have a wavelength equal to (circle one answer) use Planck's constant h= 6.625 x10-34 m2 kg / s and c = 3.00 x 108 m/s a. 700 nm b. 621 nm c. 550 nm d. 400 nm e. 500 nm

e. 500 nm

39..A metal has a work function of 2.48 eV = 4.0 x 10-19J. To produce a photoelectron with zero energy incoming light must have a wavelength equal to (circle one answer) use Planck's constant h= 6.625 x10-34 m2 kg / s and c = 3.00 x 108 m/s a. 700 nm b. 621 nm c. 550 nm d. 400 nm e. 500 nm

e. 500 nm

29. The speed of light is 3.0 x 108 m/s. If the wavelength of a light wave is 500 x 10-9 meters, what is its frequency (circle one answer)? a. 5.0 x 1014 Hz b. 6.0 x 1018 Hz c. 5.0 x 1018 Hz d. 6.0 x 1020 Hz e. 6.0 x 1014 Hz

e. 6.0 x 1014 Hz

2. In the Bohr model an atom is in the n= 1 state. It can go to the n=3 state by absorbing (circle one answer) ? a . a photon whose energy is exactly equal to the energy difference between the n= 3 and n=1 state b. two photons of any frequency as long as their total energy is equal to the energy difference between the n= 3 and n=1 state c. two photons, one of whose energy is exactly equal to the difference between the n = 3 and n=2 state and the other whose energy is exactly equal to the difference between the n= 2 and n=1 states d. both a and b are correct e. both a and c are correct f. both b and c are correct

e. both a and c are correct

38.. White light is incident on a thin film of gasoline on a water surface. The thickness of the thin film is exactly half the wavelength of a. blue b. green c. red d. orange e. cyan f. magenta g. yellow

e. cyan

16.. You are deep diving in the ocean at a depth of 100 meter below the surface. You are carrying a white ball in your hand. What color does the ball appear to be (circle one answer) ? a. red b. orange c. yellow d. magenta e. black f. blue

f. blue

22. You are deep diving in the ocean at a depth of 100 meter below the surface. You are carrying a magenta ball in your hand. What color does the ball appear to be (circle one answer) ? a. red b. orange c. yellow d. magenta e. black f. blue

f. blue

14. We look at an object that is bright red at a depth of 100 m in the ocean. What color does it appear to be (circle one answer) ? a. White b. Magenta c. yellow d. blue e. red f. green g. cyan h. black

h. black

25. A red object is illuminated with yellow light only. What color does it appear to be (circle one answer) ? a. white b. magenta c. yellow d. blue e. green f. black g. cyan h. red

h. red

The energy of the incoming photon of light must be exactly 2.48 eV = 4.0 x 10-19J.

ε = h c/λ = (6.625 x10-34 m2 kg /s)( 3 x 108m/s)/λ 4.0 x 10-19J = (6.625 x10-34 m2 kg /s)( 3 x 108m/s)/λ λ = {(6.625 x10-34 m2 kg /s)( 3 x 108m/s)}/ 4.0 x 10-19J = 500 x 10-9 m = 500 nm