Glass Slab Emergent Ray Direction Explained
When a ray of light passes through a rectangular glass slab, it undergoes refraction twice: once upon entering the slab and again upon exiting.
First Refraction: Light enters the glass slab from air. Since glass is optically denser than air, the light ray bends towards the normal.
Second Refraction: The light ray exits the slab from the parallel face back into the air. As it moves from a denser medium (glass) to a rarer medium (air), the light ray bends away from the normal.
Crucially, because the entry and exit faces of the rectangular slab are parallel, the angle of incidence at the first surface equals the angle of emergence at the second surface relative to the normal. This geometry ensures that the emergent ray is parallel to the original incident ray. The ray experiences a lateral displacement but maintains its original direction.
Therefore, the emergent ray is parallel to the incident ray.
Important Questions from Refraction and Reflection
A convex lens of focal length f will form a magnified real image of an object, if the object is placed.
A ray of light travelling in the direction \(\frac{1}{2} (\hat i + \sqrt 3 \hat j)\) is incident on a plane mirror. After reflection it travels along the direction \(\frac{1}{2} (\hat i - \sqrt 3 \hat j)\) The angle of incidence is:
Twinkling of stars is due to atmospheric
An optical fibre has a core material of refractive index of 1.55 and cladding material of refractive index of 1.50. The numerical aperture of the fibre is
- The refracting angle of a prism is $A$. The refractive index of the material of the prism is $\frac{1+\cos A}{\sin A}$. The angle of minimum deviation is:
