Scattering of Light / प्रकाश का प्रकीर्णन
The source describes scattering as deviation of light in different directions when light strikes suspended particles whose sizes are of the order of the wavelength of light.
जब light ऐसे suspended particles पर strike करती है जिनका size wavelength के order का होता है, तो light different directions में deviate होती है। इसे Scattering of Light कहा जाता है।
- Scattering is maximum for violet according to the source. / Violet light का scattering maximum बताया गया है।
- Scattering is minimum for red. / Red light का scattering minimum होता है।
Why is the Sky Blue? / आकाश नीला क्यों दिखाई देता है?
The source associates the blue colour of the sky with scattering of blue and violet light.
Source sky के blue colour को blue और violet light के scattering से associate करता है।
Red Sunrise and Sunset / सूर्योदय एवं सूर्यास्त के समय लाल रंग
The brilliant red colour of the rising and setting Sun is also attributed to scattering in the source.
Human Eye / मानव नेत्र
The human eye is described as an optical instrument similar to a camera. It forms a real image of an object on the retina.
Human Eye camera की तरह optical instrument है और object की real image retina पर form करती है।
Least Distance of Distinct Vision / स्पष्ट दृष्टि की न्यूनतम दूरी
The source gives the least distance of distinct vision as 25 cm.
Least Distance of Distinct Vision = 25 cm.
Myopia / निकट दृष्टिदोष
A person with myopia can see nearby objects but distant objects are not clearly visible.
Myopia में व्यक्ति near objects को clearly देख सकता है लेकिन distant objects clear नहीं दिखाई देते।
Correction: Concave Lens / सुधार: अवतल लेंस
Hypermetropia / दूर दृष्टिदोष
A hypermetropic eye sees distant objects clearly but nearby objects are not clearly visible.
Hypermetropia में distant objects clearly दिखाई देते हैं लेकिन near objects clear नहीं होते।
Correction: Convex Lens / सुधार: उत्तल लेंस
Presbyopia / प्रेसबायोपिया
The source describes this defect as a condition in which both near and far objects are not clearly visible.
Correction in source: Bifocal Lens / सुधार: Bifocal Lens
Astigmatism / दृष्टिवैषम्य
In astigmatism, horizontal and vertical lines are not seen clearly according to the source.
Astigmatism में horizontal और vertical lines clearly दिखाई नहीं देतीं।
Correction: Suitable cylindrical lenses / सुधार: उपयुक्त Cylindrical Lens
Microscope / सूक्ष्मदर्शी
A simple microscope is a convex lens of small focal length.
Simple Microscope small focal length वाला convex lens है।
A compound microscope is a combination of two convex lenses called objective and eyepiece.
Compound Microscope में two convex lenses—Objective तथा Eyepiece—का combination होता है।
Astronomical Telescope / खगोलीय दूरबीन
The source describes its objective as a convex lens of large aperture and large focal length, while its eyepiece is a convex lens of small aperture and small focal length.
Exam Revision / परीक्षा पुनरावृत्ति
- Least distance of distinct vision → 25 cm
- Myopia → Concave lens
- Hypermetropia → Convex lens
- Presbyopia → Bifocal lens in source
- Astigmatism → Cylindrical lens
- Simple microscope → Convex lens
- Sky colour → Scattering