Why does white light split into different colours when passing through a prism but not when passing through a glass slab?
Because a prism has non-parallel sides
A glass slab has two parallel refracting faces. Light bends towards the normal as it enters and by exactly the same amount away from the normal as it leaves, so the emergent ray is parallel to the incident ray and every colour is displaced equally.
A prism has two refracting faces inclined to each other, so the second refraction adds to the first instead of cancelling it.
Each colour has its own refractive index in glass (violet the highest, red the lowest), so with non-parallel faces each colour emerges along a different direction and the beam spreads out into a spectrum.
Hence, the answer is because a prism has non-parallel sides.
Similar Questions
Which of the following is NOT the correct use of a concave mirror?
The image formed by a concave lens for an object at infinity is:
An object is placed at a distance of 40 cm from a convex lens of focal length 10 cm, such that an image is formed at a distance of X cm from the lens. What is the value of X?
When a parallel beam of light passes through a convex lens, after refraction it:
An image is formed at a distance of 30 cm from a convex mirror when the object is placed 40 cm from the mirror. The magnification produced by the mirror will be _______.
A science fair project uses a convex mirror to monitor a hallway. If a person stands at various distances from the mirror, what remains constant about the images formed, regardless of their position?
A student observes that the image formed by a lens is twice the size of the object and is real. Where is the object placed relative to the lens?
How is the object distance measured in the sign convention for spherical lenses?
The magnification of a concave mirror is −1. Which of the following statements is correct about the position of the object?
The power of a lens is given as the reciprocal of its:
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:
