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MediumQ. No. what-is-the-wavelength-range-of-visible-light-in-angstrom-units
What is the wavelength range of visible light in Angstrom units?
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A390-780 Å
B3900-7400 Å
C100-400 Å
D7800-10000 Å
Correct Answer: 3900-7400 Å
Wavelength can be expressed in different units and converting between them is important. Option A (390-780 Å) is wrong. This confuses nm values with Angstrom values. 390-780 nm is the correct range in nanometres. Since 1 nm = 10 Angstrom, the Angstrom range would be 10 times larger: 3900-7800 Å not 390-780 Å. Option B (3900-7400 Å) is CORRECT. The image states: दृश्य स्पेक्ट्रम में तरंगदैर्ध्य की सीमा क्या होती है — 3900-7400A. This is the visible light range expressed in Angstrom (Å) units. The conversion: 1 Å = 0.1 nm = 10⁻¹⁰ m. So 390 nm = 3900 Å and approximately 740-780 nm = 7400-7800 Å. Note: The image states 3900-7400 Å which is the commonly used exam value. Option C (100-400 Å) is wrong. This range in Angstrom units corresponds to extreme UV and soft X-rays (10-40 nm) which are invisible and harmful. Option D (7800-10000 Å) is wrong. This range corresponds to near-infrared radiation (780-1000 nm) which is invisible to the human eye and used in remote controls and night vision.
FAQ
Common questions and clear answers for this topic.
Optics is the branch of physics that studies the behavior of light, including its reflection, refraction, and interaction with lenses and mirrors.
Reflection is the bouncing back of light when it strikes a surface, while refraction is the bending of light as it passes from one medium to another with a different optical density.
A lens is a transparent optical device with curved surfaces that refracts light to converge or diverge rays, commonly classified as convex (converging) or concave (diverging).
The speed of light in a vacuum is approximately 3 x 10^8 meters per second, denoted by the symbol c.
Total internal reflection occurs when light traveling from a denser medium to a rarer medium strikes the boundary at an angle greater than the critical angle, causing it to be completely reflected back into the denser medium.
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