Download Wave Nature of Light Practice Test

Name: _____________________________
SPH 4UO
Unit #4
Wave Nature of Light Practice Test
PART A: Multiple Choice
(8 marks)
1) A source S generates circular waves on a lake. If the distance between adjacent wave crests
is 2.50 m and the wave speed in 10 m/s, then the frequency of the source is closest to:
(a) 0.25 Hz
(b) 7.5 Hz
(c) 2.5 Hz
(d) 25 Hz
(e) 4.0 Hz
2) A two point source interference pattern is generated in a ripple tank. Point P, on the second
nodal line, is located 28 cm from one source and 37 cm from the other. The wavelength of
the waves is:
(a) 18 cm
(d) 6.0 cm
(b) 14 cm
(e) 4.5 cm
(c) 9.0 cm
3) Diffraction gratings produce brighter interference patterns because:
(a) The slits are wider, more numerous, and farther apart.
(b) The slits are narrower, more numerous and farther apart.
(c) The film used is much more transparent.
(d) The slits are narrower, more numerous and closer together.
(e) The light is reflected not transmitted.
4) Which of the following properties of light cannot be explained by the particle theory but can
easily be explained by the wave theory?
(a) Rectilinear propagation.
(b) Transmission in a vacuum.
(c) Refraction.
(d) Dispersion
(e) Diffraction
5) The statement regarding the polarization of light that is false is:
(a) Light can become polarized by reflection.
(b) Polarizing filters are used in some sunglasses to reduce glare.
(c) Polarization provided proof that light is a transverse wave.
(d) Polarization provided proof that light is a longitudinal wave.
(e) Light can become polarized by passing through a polarizing filter.
6) The type of electromagnetic radiation that travels at the greatest speed is:
(a) Radio waves
(b) Visible light
(c) X rays
(d) Gamma rays
(e) They all travel at the same speed.
PART B: Short Answer
1) Sound diffracts easily, light does not. Explain why.
(2 marks)
2) Just before the Sun sets, a driver encounters sunlight reflecting off the side of a building.
Will polarized sunglasses stop this glare? Explain.
( 3 marks)
PART B: Calculations
1) A concert is being held in an open field. Two speakers are separated by 7.00 m. As an
aid in arranging the seating, both speakers operate in phase and produce an 85 Hz bass
tone simultaneously. A centre line is marked out in front of the speakers, perpendicular
to the midpoint of the line between the speakers. Determine the smallest angle, relative
to either side of this reference line, which locates places where the audience has trouble
hearing the 85 Hz bass tone. (Assume that the speed of sound is 346 m/s)
(5 marks)
2) Two slits are 0.158 mm apart. A mixture of red light (λ = 665 nm) and yellow-green
light (λ = 565 nm) falls on the slits. A screen is located 2.2 m away. Find the distance
between the third-order red fringe and the third-order yellow-green fringe.
(5 marks)
3) A non-reflective coating of magnesium fluoride (n=1.38) covers the glass of a camera
lens. If the coating prevents the reflection of yellow-green light (λ=565 nm), determine
the minimum non-zero thickness of the coating.
(5 marks)
4) Red light (wavelength of 640 nm) passes through a single slit and creates an interference
pattern on a screen that is placed 2.0 m away. If the light produces a central maximum
that is 7.1 cm wide, determine the width of the opening that the light passes through.
(4 marks)
5) A diffraction grating gives a first order maximum at an angle of 25.0 for 470 nm violet
light.
(5 marks)
a) Determine the spacing of the lines of the grating.
b) Calculate the number of lines per centimetre in the grating.