Physics 11 Waves and Lenses and Mirrors Sample Test
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Name:___________
29
c=3.00 x 108 m/s
nwater = 1.33
nair = 1.00029
ni sini = nr sinr
T=1/f
v = f 
nglass= 1.52
vmaterial = c / nmaterial
ndiamond = 2.42
1 / f = 1 / d o + 1 / di
m= hi/ho
nethanol = 1.36
m = -di/do
Short answers 1 mark each – remember sig. fig.s and units
1. What is the speed of light in diamond ? (1 mark)
2. Since the speed of light in ethanol is 2.21 x 108 m/s, what is the frequency of yellow light in ethanol if the
light has a wavelength of 556 nm ? (1 mark)
3. Waves passing a meter stick stuck upright in the shoreline go as high as 85cm and as low as 45 cm on the
stick. What is the amplitude of these waves? (1 mark)
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4. Is a sound wave in air transverse or longitudinal? ____________________________________
5. Describe what happens when we say two waves are constructively interfering? (2 marks)
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6. Light from the setting sun enters the earth's atmosphere from the vacuum of space and refracts at an angle
of 88.00o What is the incident angle of the light in space? (give answer to 2 decimals)(2 marks)
7. What is the critical angle for light leaving ethanol into air ?(2 marks)
Longer answer : show all work for full marks.
1. A concave mirror with a focal length of 9.0 cm has an object positioned 11.50 cm in front of it.
a) Calculate the position of the image and the magnification factor of the mirror. (4 marks)
b) Is the image REAL or VIRTUAL ? _________________________________________________
c) Is the image UPRIGHT or INVERTED (upside-down)? ________________________________________
2. A concave lens is used on an object that is only 2.9 cm away, and creates an image that is right side up and
0.666 times as large. What is the distance to the image and what is the focal length of the lens? (4 marks)
3. How far from a candle should I place a convex lens ( f=30 cm) so that the image of the candle is exactly the
same size? (1 mark)
4. Trace rays in these diagrams (convex lens, concave mirror) and locate and draw the images: (4 marks
each)The focal points are at the marked locations on the principal axis.
Extra copy of question 4 in case you blew it and weren't using pencil (still only 4 marks each)