11 IGCSE PHYSICS 0625
YEAR 10
REVISION EXERCISE ON REFRACTION
Ms FATEN, Ms sreerekha,Mr Lawrence
TEACHERS: MR. MR. LAWRENCE & MS. FATEN
NAME…………………………………………..DATE…………
Critical angle(C)
This is the angle of incidence in the dense material which causes the angle of
refraction to be 900.
𝒔𝒊𝒏𝟗𝟎
𝟏
= 𝒏 =𝒔𝒊𝒏𝒄
𝒔𝒊𝒏𝑪
𝟏
𝒔𝒊𝒏𝒄 =
𝒏
𝟏
For glass n= 1.5:
𝒔𝒊𝒏𝒄 = 𝟏.𝟓 =0.6667
C=41.80
Total Internal reflection.
Complete reflection of light in the dense material when incident angle is
greater than critical angle.
Conditions for total internal reflection to Occur:
1. Light travelling from dense to less dense.
2. Angle of incidence greater than critical angle.
Applications of Total Internal Reflection
1. Reflective road signs
2. Optical Fibres
3. Endoscopes
4. Periscopes
Refracting prisms. They are used to refract light in many optical
instruments.
1. The diagram shows a 45o prism made of glass and a ray of
light entering the prism from air. Show the path of the ray
through the prism and back into the air.
1
2. A light ray from air travels into a medium X as shown in
Fig.12.8. What is the refractive index of medium X.
3. (a) Define critical ANGLE
(b) State two conditions for total internal reflection to
occur
(i)
(ii)
(c) Find the critical angle in a material of refractive index of 1.2.
4.
5.
2
6.
7.
8.
3
9.
10.
4
11.
12.
5
13.
14.
15.
6
16.
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7
18.
19.
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8
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22.
9
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10
25.
11
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12
28.
1.
13
29.
14
30.
15
31.
16
32.
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33.
18
34.
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20