A grating can spread white light out into a spectrum of colors because of – [Free] B28
A grating can spread white light out into a spectrum of colors because of the property of interference. reflection. diffraction. dispersion.
Answer
How a Diffraction Grating Produces a Spectrum of Light
Key Concept
A diffraction grating is an optical element containing thousands of tiny, evenly spaced parallel lines or slits. When white light (a mixture of many wavelengths) interacts with this periodic structure, the phenomenon of diffraction occurs.
Step‑by‑Step Explanation
1. Wavefront Interaction
Each slit in the grating acts as a new source of secondary wavelets, causing the incident wavefronts to spread.
2. Angular Separation
Because every wavelength bends (diffracts) by an amount inversely related to its length, the outgoing waves leave at slightly different angles. This angular difference is called angular separation.
3. Visible Spectrum Formation
The separated beams overlap on a screen (or in your eye), unveiling a continuous band of colors — red through violet — instead of a single white patch. The pattern’s order (1st, 2nd, etc.) reflects successively larger angles and clearer color separation.
Why Not Reflection or Dispersion?
Reflection merely changes the light’s direction as a whole, while dispersion in a prism relies on variation of refractive index, not the periodic structure. In a grating, constructive interference + diffraction line spacing is what isolates the wavelengths.
Practical Uses
- Spectrometers for chemical analysis
- CD/DVD data reading (tracks act as miniature gratings)
- Astronomy for stellar composition studies