Which light is used in Newton's ring experiment?
1 Answer
In Newton's Ring experiment, **monochromatic light** is typically used.
### Explanation:
1. **Monochromatic Light**:
- Monochromatic light is light of a single wavelength (color). Common sources are sodium vapor lamps, producing a yellow light with a wavelength of around \(589 \, \text{nm}\).
- The use of monochromatic light ensures clear and well-defined interference fringes. If white light (composed of multiple wavelengths) were used, overlapping fringes from different wavelengths would blur the pattern, making it difficult to analyze.
2. **Why Monochromatic Light?**
- The experiment involves observing the interference pattern created by the reflection of light between a flat glass surface and a curved glass lens. These interference patterns depend on the wavelength of the light used.
- If multiple wavelengths (e.g., white light) are used, each wavelength would form its own interference pattern, leading to a mix of colors and making the rings indistinct.
3. **Common Light Sources**:
- **Sodium Lamp**: Produces monochromatic yellow light, commonly used in optics experiments due to its stable wavelength.
- **Laser Light**: In modern setups, a laser (e.g., helium-neon laser) may be used for its highly monochromatic and coherent nature, providing sharper fringes.
4. **Alternative Approaches**:
- If the goal is to observe interference in a broader sense, sometimes white light is used, but in such cases, only a few central fringes are visible and distinguishable due to limited overlap.
In conclusion, **monochromatic light**, like that from a sodium lamp or laser, is the preferred choice for Newton's Ring experiment to produce clear and precise interference fringes.
### Explanation:
1. **Monochromatic Light**:
- Monochromatic light is light of a single wavelength (color). Common sources are sodium vapor lamps, producing a yellow light with a wavelength of around \(589 \, \text{nm}\).
- The use of monochromatic light ensures clear and well-defined interference fringes. If white light (composed of multiple wavelengths) were used, overlapping fringes from different wavelengths would blur the pattern, making it difficult to analyze.
2. **Why Monochromatic Light?**
- The experiment involves observing the interference pattern created by the reflection of light between a flat glass surface and a curved glass lens. These interference patterns depend on the wavelength of the light used.
- If multiple wavelengths (e.g., white light) are used, each wavelength would form its own interference pattern, leading to a mix of colors and making the rings indistinct.
3. **Common Light Sources**:
- **Sodium Lamp**: Produces monochromatic yellow light, commonly used in optics experiments due to its stable wavelength.
- **Laser Light**: In modern setups, a laser (e.g., helium-neon laser) may be used for its highly monochromatic and coherent nature, providing sharper fringes.
4. **Alternative Approaches**:
- If the goal is to observe interference in a broader sense, sometimes white light is used, but in such cases, only a few central fringes are visible and distinguishable due to limited overlap.
In conclusion, **monochromatic light**, like that from a sodium lamp or laser, is the preferred choice for Newton's Ring experiment to produce clear and precise interference fringes.