Download Ray optics

 (lambda)
v
f = no. of oscillations per s [ f hertz (Hz)]
= frequency of oscillation
Is the velocity of the wave shown above
(a) v   f
(c) v 
(e) v 

f
f

(b) v 2   2  2af
1 f
(d) v  2

  
incident
beam
 
30o
Figure 1
Figure 2
For reflection of light, we have the situation shown in Figure 1.
The two plane mirrors in Figure 2 are at 90o to each other, and
the incident light beam is in the plane of the screen
By making a careful sketch of the reflection
beam in Figure 2, decide which best describes
its final outgoing path.
a)
b)
d) none of the above
c)
The index of refraction of glass decreases with increasing
wavelength in the optical region
Red light has a longer wave length then violet light
Which of the following best represents the refraction of white
light (contains all colors red to violet)
white light
white light
air
air
glass
glass
violet
(a)
red
violet
red
(b)
Snell’s law for refraction of light is n2 sin 1  n2 sin 2
where:
medium 1
c
n
v
1
medium 2

2
refracted
velocity in vacuum
velocity in medium
If the velocity of light is greater in medium 2 than medium 1, is
a ) 1  2
b) 1  2
c) 1  2
d ) None of the above
n1
n2
Total internal
reflection
1 1
Total internal reflection occurs when
a) n1  n2
b) n1  n2
n2
d) sin 1 
n1
e) b & c
n1
c) sin 1 
n2
2
For the refraction of light
from the fish on the right,
which is correct?
(a)  2  1
(b)  2  0
(c)  2  1
(d)  2  1
air
water
1
h
Use a sketch of the path of 2 light rays from the same spot on the fish
to decide if a person in the air sees the fish at depth d where
(a) d < h
(b) d = h
(c) d > h
(d) need more
information
air
water
h
From a sketch roughly to
scale, use principal rays to
determine weather the
position of the image is
approximately at
A
B
C
F1
F2
(a) A (b) B (c) C (d) D
1. Is the image
(a) virtual
(b) real
2. Is the image
(a) upright
(b) inverted
3. Is the magnification of the image
(a) >1
(b) 1
4. Is the image distance
(a) negative
(b) positive
(c) <1
D
From a sketch roughly to
scale, use principal rays to
determine whether the
position of the image is A
approximately at
B F1 C
D
(a) A (b) B (c) C (d) D (e) E
1. Is the image
(a) virtual
(b) real
2. Is the image
(a) upright
(b) inverted
3. Is the magnification of the image
(a) >1
(b) 1
4. Is the image distance
(a) negative
(b) positive
(c) <1
F2
E
#1
#2
O
F2
A F1
B
F1
F2
C
D
E
F1 shows the focal points of lens #1, and F2 for lens #2.
1. For the thin lenses above, roughly where is the final image
from the two lenses?
(a) A (b) B (c) C (d) D (e) E
2. The image distance for lens #2 is
(a) positive
(b) negative
 1
1
1
Lensmaker’s equation f  (n  1) R  R 
1
2
R is positive if C is in back of the surface.
R = 10 cm
air
R = 20 cm
n = 1.5
1. What is the focal length of the lens above?
(a) 0.025 cm (b) 40 cm
(d) 0.075 cm (e) 13.3 cm
(c) -40 cm
 1
1
1
Lensmaker’s equation f  (n  1) R  R 
1
2
R is positive if C is in back of the surface.
air
R = 10 cm
n = 1.5
1. What is the focal length of the lens above?
(a) 0.050 cm (b) 20 cm (c) -20 cm
(dc) -0.05 cm (e) not enough info to tell
air
air
Lens 1
Lens 2
 1
1
1
 (n  1)  
f
 R1 R2 
Is Lens 1
(a) Converging
(b) Diverging
(c) Neither ?
Is Lens 2
(a) Converging (b) Diverging
(c) Neither ?
air
air
Lens 1
Lens 2
 1
1
1
 (n  1)  
f
 R1 R2 
Is Lens 1
(a) Converging
Is Lens 2
(c) Neither ?
(a) Converging (b) Diverging
(c) Neither ?
(b) Diverging
Water
n =1.3
n =1.5
Glass rod
 



 
B
10 cm
A
|R| = 5 cm
Where is the image?
(a) A
(b) B
n1 n2 n2  n1
 
s s
R
n1s
(2) M  
n2 s
(1)
|R| = 10 cm
1. Is R (a) positive
oil n =1.3
glass n =1.5
15 cm
(b) negative
2. Where is the image formed from the glass surface
(a) to right of surface
(b) to left of surface
3. What is the magnification? (a) < 1
(b) >1
4. With a careful drawing and Snell’s law can
you tell whether the image is in front of or
behind the surface, without using Equation 1?
(Answer (a) for yes and (b) for no)