Question

Which of the following will not result in the splitting of white light into its component colors? (A) Dispersion through a prism (B) Diffraction through a grating (C) Refraction within a thin film (D) Reflection from an ideal convex mirror

Short answer

Reflection from an ideal convex mirror (D) will not split white light.

Step-by-step solution

Analyzing dispersion through a prism

Dispersion occurs when white light passes through a prism, splitting into its constituent colors due to different refraction angles for different wavelengths. Therefore, option (A) causes the splitting of white light.

Examining diffraction through a grating

Diffraction grating splits white light into its component colors by causing interference patterns at different angles. This means option (B) also results in the splitting of white light.

Investigating refraction within a thin film

Refraction within a thin film can also cause colors to appear due to constructive and destructive interference at different wavelengths. Hence, option (C) leads to the splitting of white light.

Studying reflection from an ideal convex mirror

An ideal convex mirror reflects light without causing dispersion or the splitting of light into its component colors. Therefore, option (D) will not result in the splitting of white light.

Key concepts

Dispersion

Dispersion is a phenomenon where white light is split into its constituent colors when it passes through a medium like a prism. This happens because different colors (wavelengths) of light bend, or refract, by different amounts.
For example, violet light bends more than red light.
This difference in bending causes the white light to spread out into a spectrum of colors, similar to a rainbow.
This is why we see various colors emerge from the other side of the prism.
Dispersion is a key principle behind many optical devices and natural phenomena, like rainbows and spectroscopy.
Understanding dispersion helps explain why prisms are used in scientific instruments to analyze light.

Diffraction Grating

A diffraction grating is an optical component with a pattern of closely spaced lines or slits.
This pattern splits light into several beams traveling in different directions.
When light hits the grating, it interferes constructively and destructively, creating an interference pattern.
For white light, this means it will be dispersed into its component colors at different angles.The diffraction grating is more precise than a prism for separating colors and is often used in spectrometers and monochromators.
Because the grating can handle a wide range of wavelengths, it can analyze complex spectra of light sources.
Understanding how a diffraction grating works reinforces the principles of wave interference and shows practical applications in technology and science.

Refraction

Refraction is the bending of light as it passes from one medium to another.
The bending occurs because light changes speed when it moves between materials with different densities, like air to glass.
This change in speed alters the direction of the light.
In thin films, refraction can cause interference patterns, leading to the appearance of colors.
This effect is due to constructive and destructive interference of light waves reflected from different surfaces of the film.
These interference patterns are what create the colorful effects seen in soap bubbles and oil slicks.
Refraction is essential for understanding lenses, microscopes, and other optical devices used to focus light.

Reflection

Reflection occurs when light bounces off a surface.
If the surface is smooth and shiny, like a mirror, the light reflects at the same angle it hits the surface.
In the case of an ideal convex mirror, reflection does not cause the splitting of white light into its component colors.
Instead, it reflects all the colors together, maintaining the white light.
Convex mirrors have a curved surface that diverges light rays, making images appear smaller and giving a wider field of view.
They are widely used for safety and decorative purposes.
Understanding reflection helps explain the behavior of light in various instruments and everyday objects, highlighting why convex mirrors do not cause dispersion.