Class 10 Science - ICSE-PHYSICS
Spectrum
The chapter 'Spectrum' in Class 10 ICSE Physics explores the fascinating phenomenon of light dispersion and the electromagnetic spectrum. Students learn how white light splits into its constituent seven colors when passing through a prism due to varying wavelengths and refractive indices. The chapter covers the formation of rainbows, the scattering of light explaining why the sky is blue and danger signals are red, and details the properties and applications of different regions of the electromagnetic spectrum from gamma rays to radio waves. This is a high-scoring theoretical and conceptual chapter frequently tested in board exams.
Start Learning FreeKey Concepts
Dispersion of Light
The splitting of white light into its component colors when passing through a transparent medium like a glass prism due to different speeds of wavelengths.
Spectrum
The band of seven colors (VIBGYOR) obtained on a screen when white light undergoes dispersion.
Angle of Deviation
The angle between the incident ray and the emergent ray after refraction through a prism. Violet light deviates the most and red deviates the least.
Electromagnetic Spectrum
The orderly arrangement of electromagnetic radiations in order of their increasing wavelengths or decreasing frequencies, ranging from gamma rays to radio waves.
Scattering of Light
The phenomenon where light is redirected in various directions when it interacts with small particles whose size is comparable to the wavelength of light.
Important Formulas
Board Exam Info
In the ICSE Physics exam, this chapter typically carries about 6 to 9 marks. Questions frequently include conceptual reasons for scattering (why the sky is blue, red danger signals), numerical problems on prism angles, identifying regions of the electromagnetic spectrum and their specific uses, and drawing ray diagrams for dispersion.
Frequently Asked Questions
Why does violet light deviate more than red light through a prism?
Violet light has a shorter wavelength and higher frequency than red light, causing it to travel slower in glass and experience a higher refractive index, resulting in greater deviation.
What is the difference between total internal reflection and dispersion?
Dispersion is the splitting of white light into its constituent colors due to refraction, whereas total internal reflection is the complete reflection of a light ray back into the denser medium when the angle of incidence exceeds the critical angle.
Why are danger signals red in color?
Red light has the longest wavelength in the visible spectrum, so it suffers the least scattering by air molecules and dust particles, allowing it to be seen from long distances.
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