Test Outline: Waves and Light



The test will cover the following subjects:





  • Theory and question based on interference in thin films


  • Other applications of Light such as coated sunglasses, polarizing filters...


  • SPHOAC/SPH4U

    Waves and Light: Review Questions



    1. The speed and the wavelength of a water wave in deep water are 18.0 cm/s and 2.0 cm, respectively. If the speed in shallow water is 10.0 cm/s, what is the corresponding wavelength?


    2. A 10 Hz water wave travels from deep water, where its speed is 40 cm/s, to shallow water where its speed is 30 cm/s. The angle of incidence is 30°. Find the following.
    3. (a) the index of refraction

      (b) the wavelengths in the two media

      (c) the angle of refraction in the shallow water



    4. (a) The velocity of a sound wave in cold air is 320 m/s, and in warm air, 384 m/s. If the wavefront in cold air is nearly linear, what will be the angle of refraction in the warm air if the angle of incidence is 30°?
    5. (b) What would be the angle of refraction if the angle of incidence were 60°? Explain your answer.



    6. Two point sources generate identical waves that interfere in a ripple tank. The sources are located 5.0 cm apart, and the frequency of the waves is 8.0 Hz. A point on the first nodal line is located 10 cm from one source and 11 cm from the other.
    7. (a) What is the wavelength of the waves?

      (b) What is the speed of the waves?



    8. A page in a student's notebook lists the following information, obtained from a ripple tank experiment with two point sources operating in phase: n = 3, x3 = 35 cm, L = 77 cm, d = 6.0 cm, q3 = 25°, and 5 crests = 4.2 cm. Determine the wavelength of the waves, using various methods.


    9. Two sources 6.0 cm apart, operating in phase, produce water waves. A student selects a point on the first nodal line and measures from it 30.0 cm to a point midway between the sources and 5.0 cm (on the perpendicular) to the right bisector.
    10. (a) What is the wavelength of the waves?

      (b) When the student selects a point on the second nodal line, he finds that it is 38.0 cm from the midpoint and 21.0 cm from the bisector. Determine the wavelength.

      (c) What would be the value of the angle q for distant points on the first and second nodal lines described above?



    11. A ripple tank wave passes from a deep to a shallow region with an angle of incidence of 60° and an angle of refraction of 45°. What are the ratios in the two media of the following?
    12. (a) the wavelengths

      (b) the velocities

      (c) the frequencies



    13. An interference pattern is set up by two point sources of the same frequency, which are in phase. A point on the second nodal line is 25 cm from one source and 29.5 cm from the other source. The speed of the waves is 7.5 cm/s. Calculate the following.
    14. (a) the wavelength

      (b) the frequency of the sources



    15. If the wavelength of orange light is 6.0 ´ 10-7 m in air, what is its frequency?
    16. The frequency of a light is 3.80 x 1014 Hz. What is its wavelength in air, in nanometres?


    17. The index of refraction of turpentine relative to air for red light is 1.47. A ray of red light ( = 6.5 ´ 10-7 m) strikes an air-turpentine boundary with an angle of incidence of 40°.
    18. (a) What is the wavelength of red light in turpentine?

      (b) What is the angle of refraction in turpentine?



    19. If the first nodal line in a single-slit diffraction pattern occurs at an angle of 15° for light with a wavelength of 580 nm, what is the width of the slit?


    20. Helium-neon laser light (l = 6.328 ´ 10-7 m) passes through a single slit with a width of 43 mm onto a screen 3.0 m away. What is the separation of adjacent minima, other than the central maximum?


    21. A radiation has a frequency of 3.75 ´ 1014 Hz. What is its wavelength? In what part of the spectrum is this radiation found? Assume that the radiation travels at the speed of light.


    22. A student doing Young's experiment measures a distance of 6.0 cm between the first and seventh nodal points on a screen located 3.0 m from the slit plate.
    23. (a) If the slit separation is 220 mm, what is the wavelength of the light being used?

      (b) What is the colour of the light?



    24. Red light, of wavelength 600 nm, passes through two parallel slits. Nodal lines are produced on a screen 3.0 m away. The distance between the 1st and the 10th nodal lines is 5.0 cm. What is the separation of the two slits?


    25. In an interference experiment, red light with a wavelength of 6.0 ´ 10-7 m passes through a double slit. On a screen 1.5 m away, the distance between the 1st and 11th dark bands is 2.0 cm.
    26. (a) What was the separation of the slits?

      (b) What would the spacing be, between adjacent nodal lines, if blue light were used? (lblue = 4.5 ´ 10-7 m)



    27. If 600 nm light falls on a single slit 1.5 ´ 10-2 mm wide, what is the angular width of the central maximum?


    28. An interference pattern is formed on a screen when helium-neon laser light is directed towards it through two slits. If the slits are 43µm apart and the screen is 2.5 m away, what will be the separation of adjacent nodal lines?


    29. When 640 nm light passes through a single slit, the central maximum produced on a screen 2.0 m away is 8.0 cm wide. What is the width of the slit?




    30. A soap film of refractive index 1.34 appears yellow ( = 5.80 x 102 nm) when viewed directly from the same side as the source of light. Calculate two possible values for the thickness of the film.
    31. A film of magnesium fluoride (n = 1.38), 1.24 x 10-5 thick, is used to coat a camera lens (n = 1.55). Are any wavelengths in the visible spectrum intensified in the reflected light?


    32. Expect a qualitative question relation to polarization of light.
    33. Expect a calculated question relation to a diffraction grating.

      TEST TOTAL will be 50 marks.




    ANSWERS:



    1. 1.1 cm
    2. a. 1.33
      b. 4 cm, 3 cm
      c. degrees
    3. a. 37 degrees

    4. b. Undefined (critical angle has been exceeded)
    5. a. 2 cm

    6. b. 16 cm/s
    7. Method 1 = 1.1 cm
    8. Method 2 = 1.0 cm

      Method 3 = 1.1 cm

    9. a. 2 cm

    10. b. 2.2 cm
      c = 9.6 degrees, 2 = 34 degrees
    11. a. 1.2

    12. b. 1.2
      c. 1.0
    13. a. 3 cm

    14. b. 2.5 Hz
    15. 5 x 1014 Hz
    16. 789 nm
    17. a. 4.4 x 10-7m

    18. b. 26 degrees
    19. 2.2 x 10-6
    20. 44 µm
    21. 800 nm
    22. a. 7.3 x 10-7 m

    23. b. Red
    24. 3.2 x 10-4 m
    25. a. 4.5 x 10-4 m
      b. 1.5 x 10-3
    26. 4.6 degrees
    27. 3.7 cm
    28. 3.2 x 10-5 m
    29. 110 nm, 329 nm
    30. 6.9 x 10-5 cm