CBSE Class 8 Science Chapter 13 Light Short Answer Type Question
Question 1. Look at figure. Can the Image of the child In It be obtained on a screen?
Answer: The image of the child cannot be obtained on the screen because the image is not real. The images formed by plane mirror are virtual, so these virtual images cannot be seen on die screen.
Question 2. What is the difference between the surfaces of a sheet of sandpaper and a mirror?
Answer: The sandpaper has a rough surface causing light that is reflected on it to be scattered at different angles. The mirror however, allows regular reflection. Sandpaper cannot produce any image, unlike the mirror due to diffused (irregular) reflection.
” CBSE Class 8 Science Chapter 13 SAQs “
Read And Learn More CBSE Class 8 Science Short Answer Questions
Question 3. Explain how do we see various objects?
Answer: Due to reflection, we can see various objects. Since, we know that, all surfaces reflect light So when light falls on them (any objects), it reflects the light. In this way, this reflected light enters our eyes and due to this, we can see the object.
Question 4. Draw figure showing the position of the plane mirror. Also, label the angle of incidence and angle of reflection on it.
Answer:
” Light Class 8 Short Answer Questions “
Question 5. “The laws of reflection only holds true for regular reflection”. Is this statement true or false? Explain your answer.
Answer: False, the laws of reflection holds for both regular and diffused reflection. In a diffused reflection, the reflecting surface being rough anil uneven, the parallel beam of light is reflected in different directions and angles.
Question 6. Explain what happens to light when It gets dispersed?Also, give an example.
Answer: Light is splitted into its constituent colours (7 colours) when it gets dispersed, e.g. rainbow formation is due to the dispersion of white light after passing through water droplets.
” Reflection of Light Class 8 “
Question 7. Which part of the eye gets affected, if someone is suffering from cataract? How is it treated?
Answer: In people suffering from cataract, the eye lens becomes cloudy. Cataract is treated by replacing the convex lens with a new artificial lens.
Question 8. Eyes of the nocturnal birds have large cornea and a large pupil. How does this structure help them?
Answer: The size of the eyes of nocturnal bird is large. Large eyes with a wider pupil, larger lens and increased retinal surface can collect more ambient light which help them to see the objects even at night easily. 
” Laws of Reflection Class 8 “
Question 9. “Though the image formation on retina is inverted but still we are able to see the erect objects”. Explain how?
Answer: Yes, it is very true to say because the formation ofimage on the retina is conveyed to brain in the form ofelectrical impulses with the help ofoptical nerves. So, brain is able to perceive an erect image ofobject with the help of electrical impulses.
Question 10. Explain in brief, how do ciliary muscles affect the functioning of eye?
Answer: As we know that, ciliary muscles can contract and relax, because of it, this can change the shape of eye lens which results in change in its focal length. So, eye lens can make image of nearby objects and also far off objects on retina.
Question 11. The picture shows the size of the pupil under two different conditions.
” Plane Mirror Image Formation “
What makes the pupil change size between conditions 1 and 2?
Answer: In condition 1, eyes get insufficient amount oflight. That’s why, the pupil expands but in condition 2, eyes get large amount of light that’s why pupil contract.
Question 13. Boojho stands at A just on the side of a plane mirror as shown In figure. Can he see himself in the mirror ? Also, can he see the image of objects situated at P, Q and R?
Answer: As Boojho is not in the range of reflecting surface rather, he is standing away from the mirror, so he cannot see himself in the mirror. But he can see the image ofP which is in the reflecting area but not of Q and R.
” Dispersion of Light into VIBGYOR “
Question 14.
- Find out the position of the Image of an object situated at A In the piano mirror.
- Can Pahell at B see this Imago?
- Can Boojho at C see this Image?
- When Pahell moves from B to C, where does the Image of A move?
” Human Eye Structure Class 8 “
Answer:
- Since, it is plane mirror, so the image is formed behind the mirror and there is a lateral inversion in it
- Yes, Paheli can see the image of object A.
- Yes, Boojho can also see the image of object A.
- No change in the position of the image of A