Samacheer Kalvi 7th Science Term 3 Unit 1 Solutions

Samacheer Kalvi 7th Science Term 3 Unit 1 Book Back Question and Answers/Solutions:

Samacheer Kalvi Class 7th Std Science Book Back 1 Mark and 2 Mark Question & Answers PDF uploaded and available below. Class 7th Standard New Syllabus 2022 to 2023 Book Back Question & Answer solutions available for both English and Tamil Medium. Class 7 New Science Book Term 3 Unit 1 – Light Answers/Solutions Guide are provided on this page. 7th Std Science Book is of 1st Term consists of 7 units, 2nd and 3rd Term consists of 6 units. All Units/Chapters of Term 1st, 2nd, 3rd Science Book Back One, and Two Mark Solutions are given below.

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Samacheer Kalvi 7th Science Book Back Chapter 1 Term 3 Answers/Solutions Guide PDF:

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7th Science – Term 3 Chapter 1

Light

I. Choose the correct option:

1. Light travels only in a ______ .It is because of this property that.
(a) curved line, shadows
(b) straight line, shadows
(c) straight line, reflection
(d) curved line and then straight line, shadows
Answer: (b) straight line, shadows

2. Light that hits a mirror gets ______
(a) Transmitted
(b) Reflected
(c) Absorbed
(d) Refracted
Answer: (b) Reflected

3. ______ surface reflects the light well
(a) Water
(b) Compact disc
(c) Mirror
(d) Stone
Answer: (c) Mirror

4. Light is a form of ____
(a) matter
(b) energy
(c) medium
(d) partical
Answer: (b) energy

5. You can see your image in polished floors, but not in wooden table because ______
(a) regular reflection takes place in wooden table and irregular reflection in polished floor
(b) regular reflection takes place in polished floor and irregular reflection in wooden table
(c) regular reflection takes place in both polished floor and wooden table
(d) irregular reflection takes place in both polished floor and wooden table
Answer: (b) regular reflection takes place in polished floor and irregular reflection in wooden table

6. Choose the translucent substance from the following
(a) glass
(b) wood
(c) water
(d) Clouds
Answer: (d) clouds

7. Reflection occurs , when the light
(a) about to reach a surface
(b) approaches a surface
(c) passes through a surface
(d) None Of these
Answer: (b) approaches a surface

8. Which of the following is the best reflector
(a) plastic plate
(b) plane mirror
(c) wall
(d) paper
Answer: (b) plane mirror

9. Sivarajan placed a meter stick in the playground at 7.00 am in the morning. How will the shadow of the stick at noon look in comparison to the one in the morning
(a) There will be no shadow
(b) The shadow will be longer and on the opposite side as the sun
(c) The shadow will be shorter and on the same side as the sun
(d) The shadow will be shorter
Answer: (d) The shadow will be shorter

10. The image formed by a pinhole camera is inverted because,
(a) light travels in straight lines
(b) light rays become laterally inverted as they pass through a pinhole camera
(c) light rays pass through the pinhole
(d) light rays get reflected
Answer: (a) light travels in straight lines

11. Which of the following facts explain how shadows are formed?
(a) Light travels in straight lines
(b) Opaque bodies do not allow light to pass through them
(c) Reflection occurs at a smooth surfaces like mirrors
(d) Lateral inversion happens
(a) both A and B
(b) both A and D
(c) both B and C
(d) only A
Answer: (a) both A and B

II. Fill in the blanks:

A plane mirror produces a _________ image
A _________ reflection helps us to see the objects.
The light ray gets _________ when it falls on any polisher surface
Sunlight is a blend of _________ colours
The splitting of white light into seven colours is called _________
The moon _________ sun light.
The sunlight can be split into its constituent colours using _________
Reflection of light from rough surface is called _________ reflection

Answer:

virtual and erect
regular
reflected
seven
dispersion
reflects
prism
irregular

III. Say TRUE or FALSE:

1.The image of right hand in a plane mirror looks like a left hand.
Answer: True

2. Rainbow is formed by dispersion of which light by water drops.
Answer: True

3. The image formed by the plane mirror is laterally inverted, hence the image seen through the periscope is also laterally inverted
Answer: False
Correct statement: The image formed by the plane mirror is laterally inverted, hence the image seen through the periscope is This is because in periscope, image is reflected by two mirrors.

4. We see planets because they reflect light from the sun
Answer: True

5. We see a book because it reflects the light that falls on its surface
Answer: True

6. The image formed in a pinhole camera is always inverted
Answer: True

7. The image formed in a pinhole camera is always the satne size as the object
Answer: False

8. The image formed in a plane mirror is upside down
Answer: False
Correct statement: The image formed in a plane mirror is erect.

9. A plane mirror is opaque Ans.
Answer: True

10. A shadow is formed on the same side of the object as the source of light.
Answer: False
Correct statement: A shadow is formed on the side of the object as the source of light.

11. We are able to see things around us with the help of regular reflection
Answer: True

12. After passing through a prism, white light splits into a band of seven colours
Answer: True

IV. Match the following:

1.	Rectilinear propagation	Primary source of light
2.	Rectilinear propagation	Non-luminous object
3.	Plane Mirror Fire fly	Periscope
4.	The Moon	Pinhole camera
5.	Wide light source	Spectrum of light
6.	Regular reflection	luminous object
7.	The sun	Penumbra
8.	Band of seven colors	Glossy surface