UPSC CAPF AC 2025 Paper 1 · Question 110
Question 110 of the UPSC CAPF (AC) 2025 Paper I (3 August 2025). Try it first, then open the answer and explanation.
When sunlight (white light) falls on a triangular glass prism, a band of colours called a spectrum is obtained. Which one among the following represents this effect appropriately?
- Reflection
- Diffraction
- Refraction
- Dispersion
जब सूर्य का प्रकाश (श्वेत प्रकाश) एक त्रिकोणीय काँच के प्रिज्म पर पड़ता है, तो रंगों का एक बैंड प्राप्त होता है जिसे स्पेक्ट्रम कहा जाता है। निम्नलिखित में से कौन-सा इस प्रभाव को समुचित रूप से दर्शाता है?
- परावर्तन (Reflection)
- विवर्तन (Diffraction)
- अपवर्तन (Refraction)
- प्रकीर्णन (Dispersion)
Show answer
Answer: (4) Dispersion
उत्तर: (4) प्रकीर्णन (Dispersion)
The splitting of white light into its constituent colours (VIBGYOR) by a prism is called dispersion; it happens because the refractive index of glass differs for different wavelengths, so violet bends the most and red the least. Refraction is the bending that causes it, but the formation of the spectrum itself is dispersion.