Short Questions with answers
1. What is light?
Answer : Light is a form of energy that enables us to see objects.
2. What is a ray of light?
Answer : A ray of light is the path along which light energy travels.
3. What is the angle of incidence?
Answer : It is the angle between the incident ray and the normal.
4. What is the angle of reflection?
Answer : It is the angle between the reflected ray and the normal.
5. State the first law of reflection.
Answer : The angle of incidence is equal to the angle of reflection.
6. State the second law of reflection.
Answer : The incident ray, reflected ray, and normal lie in the same plane.
7. What is lateral inversion?
Answer : Lateral inversion is the reversal of the left and right sides in a plane mirror.
8. What is a plane mirror?
Answer : A plane mirror is a flat, smooth surface that reflects light.
9. What is a virtual image?
Answer : A virtual image cannot be obtained on a screen.
10. What causes diffused reflection?
Answer : Irregularities in the reflecting surface cause diffused reflection.
11. What is a periscope?
Answer : A periscope is a device that uses two plane mirrors to view objects not in direct sight.
12. What is dispersion of light?
Answer : Dispersion is the splitting of white light into its constituent colors.
13. What part of the eye controls light entry?
Answer : The iris controls the amount of light entering the eye.
14. What are cones and rods in the retina?
Answer : Cones detect color and bright light, while rods detect dim light.
15. What is the blind spot?
Answer : The blind spot is the point on the retina with no sensory cells.
16. What is cataract?
Answer : Cataract is the clouding of the eye’s lens leading to blurry vision.
17. What is the Braille system?
Answer : Braille is a system of raised dots that helps visually impaired individuals read.
18. What are luminous objects?
Answer : Luminous objects emit their own light.
19. What are illuminated objects?
Answer : Illuminated objects reflect light from other sources.
20. What is a kaleidoscope?
Answer : A kaleidoscope forms patterns through multiple reflections in inclined mirrors.
Medium Questions with answers
1. What is the difference between regular and diffused reflection?
Answer : Regular reflection occurs on smooth surfaces, forming clear images. Diffused reflection occurs on rough surfaces, scattering light in all directions.
2. How is an image formed in a plane mirror?
Answer : A plane mirror reflects light rays such that they appear to converge behind the mirror. The image formed is virtual, upright, and of the same size as the object.
3. What are luminous and illuminated objects?
Answer : Luminous objects emit their own light, such as the Sun and candles. Illuminated objects reflect light from a luminous source, like the Moon.
4. What is a kaleidoscope?
Answer : A kaleidoscope is a device with multiple mirrors set at angles, creating beautiful patterns through multiple reflections. It is often used by designers for inspiration.
5. What happens when sunlight passes through a prism?
Answer : Sunlight splits into seven colors due to dispersion, forming a spectrum. This phenomenon demonstrates that white light consists of various colors.
6. What is the role of the pupil in the eye?
Answer : The pupil regulates the amount of light entering the eye by contracting in bright light and dilating in dim light.
7. What is the retina, and what are its functions?
Answer : The retina is the light-sensitive layer at the back of the eye containing rods and cones. It converts light into signals sent to the brain.
8. What are rods and cones in the retina?
Answer : Rods are sensitive to dim light and help in night vision, while cones are sensitive to bright light and detect colors.
9. What is lateral inversion in a mirror?
Answer : Lateral inversion occurs when the left and right sides of an object appear reversed in its mirror image.
10. How do periscopes work?
Answer : Periscopes use two plane mirrors placed at 45° angles to reflect light, allowing one to see objects that are not in direct line of sight.
Long Questions with answers
1. Explain the laws of reflection with an example.
Answer : The two laws of reflection are: (i) The angle of incidence is always equal to the angle of reflection. (ii) The incident ray, reflected ray, and normal lie in the same plane. For example, when light hits a mirror, the reflected ray follows these laws, forming a clear image.
2. Describe the construction and working of a kaleidoscope.
Answer : A kaleidoscope is made using three plane mirrors joined to form a prism inside a tube. The other end of the tube contains colored glass pieces and a translucent glass plate. When light enters, multiple reflections inside the mirrors create beautiful patterns.
3. What are the parts of the human eye, and their functions?
Answer : The eye has parts like the cornea (protects and refracts light), iris (controls pupil size), pupil (regulates light entry), lens (focuses light on the retina), and retina (converts light into signals for the brain). The optic nerve transmits these signals to the brain for image formation.
4. What is dispersion of light? Explain with an activity.
Answer : Dispersion is the splitting of white light into its seven constituent colors. Place a plane mirror in water so that sunlight reflects on a wall. The water and mirror act as a prism, breaking sunlight into a spectrum, similar to a rainbow.
5. What is the Braille system and how does it help visually impaired people?
Answer : The Braille system uses patterns of raised dots to represent letters, numbers, and symbols. Visually impaired individuals read by feeling these dots with their fingers. It enables them to read, write, and communicate effectively.
6. Explain the difference between luminous and non-luminous objects with examples.
Answer : Luminous objects emit their own light, such as the Sun and stars. Non-luminous objects do not emit light; they reflect light from luminous sources, like the Moon or a chair. Both types are essential for visibility.
7. How can you take care of your eyes?
Answer : Regular eye check-ups and using suitable glasses if needed are crucial. Avoid reading in dim or too bright light, and maintain a proper distance while reading. Include Vitamin A-rich foods like carrots and spinach in your diet to keep your eyes healthy.
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