Class 7 Basic Science: Chapter 02 Wonders of Visible Light - Questions and Answers


Study Notes for Class 7th Basic Science (English Medium) പ്രകാശ വിസ്മയങ്ങൾ | Text Books Solution Basic Science (English Medium) Chapter 02 Wonders of Visible Light - Teaching Manual

SCERT Solutions for STD VII Basic Science Chapterwise
ഈ അധ്യായത്തിന്റെ Teachers Handbook, Teaching Manual എന്നിവ ഡൗൺലോഡ് ചെയ്യാനുള്ള ലിങ്ക് ചോദ്യോത്തരങ്ങളുടെ അവസാനം നൽകിയിട്ടുണ്ട്.

Wonders of Visible Light - Questions and Answers & Model Questions
1. Which of the following is not relevant to a plane mirror?
(a) Causes dispersion of light
(b) Reflects light
(c) Produces lateral inversion
(d) Produces virtual image
Answer: (a) Causes dispersion of light

2.  The line drawn perpendicular to the mirror at the point of incidence is called
a) Normal
b) Incident Ray
c) Reflected Ray
d) None of the above.
Answer: a) Normal

3. The angle between the incident ray and the normal is
a) Angle of incidence
b) Angle of Reflection
c) Both
d) None
Answer: a) Angle of incidence

4. The angle between the reflected ray and the normal is
a) Angle of incidence
b) Angle of Reflection
c) Both
d) None
Answer: b) Angle of Reflection

5. The properties of the image formed by a plane mirror are
a) The size of the image will be the same as that of the object
b) The distance between the image and the mirror is equal to the distance between the object and the mirror.
c) The image will undergo lateral inversion.
d) All the above.
Answer: d) All the above.

6. Lens with a thick central portion and a thin edge is called
a) concave lens
b) convex lens
c) both
d) None.
Answer: b) convex lens

7. lens with a thin central portion and thick edges is called
a) Concave lens
b) convex lens
c) both
d) None.
Answer: a) Concave lens

8. Sunlight is
a) Red light
b) White Light
c) Yellow light
d) Blue light
Answer: b) White Light

9. What is regular reflection?
Answer: When light falls on a mirror, steel plate, smooth floor tile etc., it is reflected regularly. This is known as regular reflection.

10. What is diffused reflection?
Answer: When light falls on rough surfaces, it is reflected irregularly. This is diffuse reflection.
11. How do we see objects? Can we see objects in a dark room? 
Answer:  We can see an object when the light falling on the object is reflected into our eyes. There are no light rays in darkness. So no rays reach our eyes from objects and we are unable to see objects in the darkness.

12. Can you mark the path of light in the following pictures?

i. How does the driver see the boy crossing the road during the daytime?
ii. How is the dog seen when a torch is lighted?
Answer: 
i. The light rays fall on the body of the boy and get reflected. The reflected rays reach the eyes Of the driver. Thus the driver sees the boy.
ii. The light rays from the torch fall on the dog and get reflected. The reflected rays reach the eyes and see the dog.

13. What is a plane mirror? What are the peculiarities of its surface?
Answer: A mirror with a plane surface is called a plane mirror.
• The surface is very smooth 
• So light will reflect very well

14. What are the properties of the image formed by a plane mirror?
Answer:
The properties are given below:
1) The size of the image will be the same as that of the object.
2) The distance between the image and the mirror is equal to the distance between the object and the mirror.
3) The image will undergo lateral inversion.

15. Now, what if we look at a steel plate or an aluminium plate instead of a mirror? How does the face appear?  Note it down in your science diary.
Answer: Our face is not clearly seen

16. Can you find out the direction in which the light falling on a surface would get reflected?

Answer:
• The ray falling on the mirror is called the incident ray.
• The ray reflected from the mirror is a reflected ray.
• The line drawn perpendicular to the mirror at the point of incidence is called the normal.
• The angle between the incident ray and normal is the angle of incidence.
• The angle between the reflected ray and the normal is the angle of reflection.

17. What is reflection?
Answer: Reflection of light is the return of light that falls on a surface.

18. What is Lateral inversion?
Answer: shifting of the lateral side of the images in the opposite direction is called lateral inversion.

19. Don’t you see how the word AMBULANCE is written on vehicles. What
is the reason for writing the word with left-right change?
Answer: The drivers Of vehicles that run in front of the ambulances can identify it as they see the image of the word. ECNALUBMA is written on it laterally in the rearview mirror to allow the ambulance to overtake.

20. What is refraction?
Answer:  When light travels from one medium to another, its path undergoes a deviation. This phenomenon of light is called refraction.

21. What is Dispersion?
Answer: The phenomenon of the splitting up of white light into its component colours is dispersion.
22. Which are the colours present in White light?
Answer:  White light consists of seven colours. Violet, indigo, blue, green, yellow, orange and red is the colours.

23. What is a Rainbow?
Answer: The rainbow is a colour phenomenon that occurs when sunlight passes through water droplets in the atmosphere.

24. Three transparent objects are arranged in the path of a light beam. Which is the correct statement about them?



25. What are the uses of different mirrors?
Answer: Uses are given below:
1) concave mirror: i) Shaving mirror ii) Reflector in torch
2) convex mirror: i) Used by drivers to see the vehicles behind (rearview mirror)
3) plane mirror: i) To see our face ii) To make Kaleidoscope.

26. What are the uses of lenses?
Answer: Uses are given below:
i) We use different types of spectacles to rectify defects of vision. Different types of lenses are used in them.
ii)To see tiny letters and objects in a bigger size, we use a hand lens. This is a convex lens. The convex lens is used in equipment like microscopes, telescopes, cameras and projectors.

27. Rewrite arranging the second and the third columns suitably to match the first column.


28. Is the actual position of a fish in water the same as the position at which it appears to us? Why?
Answer: No, The fish seen in the water will usually appear to be at a different depth than it actually is, due to the refraction of light rays as they travel from the water into the air.

29. In which of the following do we see images more clearly - a new steel vessel or a used one? Why?
Answer: Used vessel has a rough surface, so light undergoes diffused reflection in it. But for a new steel vessel due to its smooth surface light undergoes regular reflection. We can see the clear image only in regular reflection so the answer is NEW STEEL VESSEL.







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