Science
(a) Draw a ray diagram to show the refraction of a ray of light through a rectangular glass slab when it falls obliquely from air into glass.
(b) State Snell’s law of refraction of light.
(c) Differentiate between the virtual images formed by a convex lens and a concave lens on the basis of :
- object distance, and
- magnification
Refraction Plane Surfaces
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Answer
(a) The ray diagram showing the refraction of a ray of light through a rectangular glass slab when it falls obliquely from air into glass is given below :
(b) Snell's law states that the ratio of the sine of the angle of incidence (i) to the sine of the angle of refraction (r) is a constant for a given pair of media i.e.,
where n21 is the refractive index of the second medium with respect to the first.
(c)
| Basis | Convex Lens | Concave Lens |
|---|---|---|
| 1. Object distance | A virtual image is formed when the object is placed between the optical centre and the focus (F). | A virtual image is formed for all positions of the object. |
| 2. Magnification | The image is virtual, erect, and magnified. | The image is virtual, erect, and diminished. |
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