To find the critical angle for the glass-air interface, we can follow these steps:
### Step 1: Understand the concept of critical angle
The critical angle is the angle of incidence above which total internal reflection occurs when light travels from a denser medium (glass) to a less dense medium (air).
### Step 2: Use the formula for critical angle
The formula for the critical angle (Ic) is given by:
\[
\sin(I_c) = \frac{n_2}{n_1}
\]
where \( n_1 \) is the refractive index of the denser medium (glass) and \( n_2 \) is the refractive index of the less dense medium (air).
### Step 3: Identify the refractive indices
For glass, the refractive index \( n_1 \) is approximately \( \frac{3}{2} \) (or 1.5), and for air, the refractive index \( n_2 \) is approximately 1.
### Step 4: Substitute the values into the formula
Using the values:
\[
\sin(I_c) = \frac{n_2}{n_1} = \frac{1}{\frac{3}{2}} = \frac{2}{3}
\]
### Step 5: Calculate the critical angle
Now, we need to find the angle whose sine is \( \frac{2}{3} \):
\[
I_c = \sin^{-1}\left(\frac{2}{3}\right)
\]
### Step 6: Use a calculator to find the angle
Calculating this gives:
\[
I_c \approx 41.81^\circ
\]
### Step 7: Round to the nearest degree
Rounding this value gives us:
\[
I_c \approx 42^\circ
\]
### Final Answer
Thus, the critical angle for the glass-air interface is approximately **42 degrees**.
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A beam consisting of red, blue and yellow colours is incident normally on the face AB of an isosceles right angled prism ABC as shown in Fig. 6.5. Complete the diagram to show the refracted and the emergent rays. Given that the critical angle of glass-air interface for yellow colour is 45^(@)
(a) Figure below shows a parallel beam of monochromatic light incident on a convex sperical surface, radius of curvature R=30 cm, which separates glass (refractive). Find the distance of image formed. (b) A ray of light which is incident in air on the surface of a glass block is deviated through 15^(@) . The angle of incidence in air is 60^(@) . what is the angle of refraction in glass ? Also, claculate the critical angle for a glass-air interface.
A glass plate has a thicknes t and refractive index mu . The angle of incidence of a ray from air into the plate is equal to the critical angle for glass air intrerface. The lateral shift (perpendicular distance between incident ray and emergent ray) of ray is given by
State the approximate value of the critical angle for (a) glass-air surface (b) water-air surface.
A ray of light travelling in glass having refractive index _(a)mu_(g)=3//2 is incident at a critical angle C on the glass air interface. If a thin layer of water is poured on glass air interface, then what will be the angle of emergence of this ray in air when it emerges from water air inteface?
The Brewster angle for the glass air interface is 54.74^(@) if a ray of light going from air to glass strikes at an angle of incidence 45^(@) then the angle of refraction is
The Brewster angle for the glass air interface is 54.74^(@) if a ray of light going from air to glass strikes at an angle of incidence 45^(@) then the angle of refraction is
The critical angle for glass-air is 45^(@) for the light of yellow colour. State whether it will be less than, equal to, or more than 45^(@) for (i) red light, and (ii) blue light ?
If the polarising angle for air glass interface is 56.3^(@) , what is the angle of refraction in glass ?
Critical angle of glass is theta_(1) and that of water is theta_(2) . The critical angle for water and glass surface would be (mu_(g)=3//2, mu_(w)=4//3)
ICSE-REFRACTION OF LIGHT AT PLANE SURFACES-EXERCISE-4(D) MULTIPLE CHOICE TYPE
