18 Questions
What are the two laws of reflection?
Reflection angle equals incident angle, and incident ray, reflected ray, and normal all lie on the same plane
Why is red colour selected for danger light signals?
Red light is least scattered by fog or smoke, ensuring better visibility
What is meant by the term power of accommodation? Name the part of our eye that is responsible for the power of accommodation.
Power of accommodation refers to the ability of the eye to focus on objects at varying distances. The iris is responsible for the power of accommodation.
What is dispersion of light?
Dispersion of light is the splitting of white light into its constituent colors
Which type of mirror is used outside the driver's side of a vehicle?
Convex mirror
A doctor has prescribed a corrective lens of power +1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging?
-0.67m, diverging lens
Why is a convex mirror preferred as a rear-view mirror in vehicles?
It provides a wider field of view
What is the definition of refraction of light?
Change in direction of light as it passes from one medium to another
What is the mirror image of the word 'AMBULANCE'?
ECNALUBAM
What is the mirror formula used in optics?
$rac{1}{f} = rac{1}{v} + rac{1}{u}$
What are the two laws of reflection?
Law of reflection and law of reversibility
List three differences between real and virtual images.
Real images can be projected on a screen, virtual images cannot be projected.
Why is red color selected for danger light signals?
Red light has the longest wavelength
Name the three common defects of vision and their causes.
Nearsightedness (myopia), farsightedness (hypermetropia), astigmatism
What are two uses of concave mirrors?
Concave mirrors are used in solar cookers and make-up mirrors
Define power of lens and write its S. I. unit.
$P = \frac{1}{f},$ where $f$ is the focal length; SI unit: dioptre (D)
Q1 What is your Name?
Ramesh
Q2 What is Apple?
fruit
Study Notes
Laws of Reflection
- The two laws of reflection are: the incident ray, reflected ray, and normal to the mirror at the point of incidence all lie in the same plane, and the angle of incidence is equal to the angle of reflection.
Color Selection
- Red color is selected for danger light signals because it has the longest wavelength and is least scattered by the atmosphere, making it more visible from a distance.
Power of Accommodation
- The power of accommodation is the ability of the eye to focus on objects at different distances by changing the curvature of the lens.
- The part of the eye responsible for the power of accommodation is the ciliary muscle.
Dispersion of Light
- Dispersion of light is the separation of white light into its component colors due to the different refractive indices of the medium for different wavelengths.
Mirrors in Vehicles
- A convex mirror is used outside the driver's side of a vehicle because it provides a wider field of view and reduces the blind spot.
Lenses
- A corrective lens of power +1.5 D has a focal length of 1/1.5 = 0.67 m.
- The prescribed lens is converging.
- Convex mirrors are preferred as rear-view mirrors in vehicles because they provide a wider field of view and reduce the blind spot.
Refraction
- Refraction of light is the bending of light as it passes from one medium to another with a different optical density.
Mirror Image
- The mirror image of the word 'AMBULANCE' is 'ECNALUBMA'.
Mirror Formula
- The mirror formula is 1/f = 1/do + 1/di, where f is the focal length, do is the object distance, and di is the image distance.
Differences between Real and Virtual Images
- Real images are formed on a screen, whereas virtual images are not formed on a screen.
- Real images are inverted, whereas virtual images are upright.
- Real images are formed by converging lenses, whereas virtual images are formed by diverging lenses.
Color Selection
- Red color is selected for danger light signals because it has the longest wavelength and is least scattered by the atmosphere, making it more visible from a distance.
Defects of Vision
- The three common defects of vision are myopia (nearsightedness), hyperopia (farsightedness), and astigmatism.
- Causes: myopia is caused by the elongation of the eyeball, hyperopia is caused by the shortening of the eyeball, and astigmatism is caused by the irregular curvature of the cornea.
Uses of Concave Mirrors
- Concave mirrors are used in solar ovens to focus sunlight and in makeup mirrors to provide a magnified image.
Power of Lens
- The power of a lens is the degree to which it converges or diverges light.
- The S.I. unit of power of a lens is diopter (D).
Test your knowledge of the laws of reflection, differences between real and virtual images, reasons for selecting red color for danger light signals, causes of hypermetropia, common defects of vision, uses of concave mirrors, and ray diagrams. This quiz covers important concepts from the chapters 'The Human Eye' and 'The Colourful World' in class 10 physics.
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