Tamil Nadu Board of Secondary EducationSSLC (English Medium) Class 9th

# Tamil Nadu Board Samacheer Kalvi solutions for Class 9th Science Answers Guide chapter 6 - Light [Latest edition]

#### Chapters ## Chapter 6: Light

Exercise
Exercise [Pages 77 - 78]

### Tamil Nadu Board Samacheer Kalvi solutions for Class 9th Science Answers Guide Chapter 6 Light Exercise [Pages 77 - 78]

#### Choose the correct answer.

Exercise | Q I. 1. | Page 77

A ray of light passes from one medium to another medium. Refraction takes place when angle of incidence is ______.

• 45°

• 90°

Exercise | Q I. 2. | Page 77

______ is used as reflectors in torchlight.

• Concave mirror

• Plane mirror

• Convex mirror

Exercise | Q I. 3. | Page 77

We can create enlarged, virtual images with ______.

• concave mirror

• plane mirror

• convex mirror

Exercise | Q I. 4. | Page 77

When the reflecting surface is curved outwards the mirror formed will be ______.

• concave mirror

• convex mirror

• plane mirror

Exercise | Q I. 5. | Page 77

When a beam of white light passes through a prism it gets ______.

• reflected

• only deviated

• deviated and dispersed

Exercise | Q I. 6. | Page 77

The speed of light is maximum in ______.

• vacuum

• glass

• diamond

Exercise | Q II. 1. | Page 77

State whether true or false. If false, correct the statement.

The angle of deviation depends on the refractive index of the glass.

• True

• False

Exercise | Q II. 2. | Page 77

State whether true or false. If false, correct the statement.

If a ray of light passes obliquely from one medium to another, it does not suffer any deviation.

• True

• False

Exercise | Q II. 3. | Page 77

State whether true or false. If false, correct the statement.

The convex mirror always produces a virtual, diminished and erect image of the object.

• True

• False

Exercise | Q II. 4. | Page 77

State whether true or false. If false, correct the statement.

When an object is at the centre of curvature of concave mirror the image formed will be virtual and erect.

• True

• False

Exercise | Q II. 5. | Page 77

State whether true or false. If false, correct the statement.

The reason for brilliance of diamonds is total internal reflection of light.

• True

• False

#### Fill in the blanks.

Exercise | Q III. 1. | Page 77

In going from a rarer to denser medium, the ray of light bends ______.

Exercise | Q III. 2. | Page 77

The mirror used in search light is ______.

Exercise | Q III. 3. | Page 77

The angle of deviation of light ray in a prism depends on the angle of ______.

Exercise | Q III. 4. | Page 77

The radius of curvature of a concave mirror whose focal length is 5cm is ______

Exercise | Q III. 5. | Page 77

Large ______ mirrors are used to concentrate sunlight to produce heat in solar furnaces.

Exercise | Q IV. | Page 77

Match the following.

 1 Ratio of height of image to height of object. Concave mirror 2 Used in hairpin bends in mountains. Total internal reflection 3 Coin inside water appearing slightly raised. Magnification 4 Mirage Convex mirror 5 Used as Dentist’s mirror. Refraction

#### Assertion and reason type questions.

Exercise | Q V. 1. | Page 77

Assertion: For observing the traffic at a hairpin bend in mountain paths a plane mirror is preferred over convex mirror and concave mirror.

Reason: A convex mirror has a much larger field of view than a plane mirror or a concave mirror.

• If both assertion and reason are true and reason is the correct explanation.

• If both assertion and reason are true and reason is not the correct explanation.

• If assertion is true but reason is false.

• If assertion is false but reason is true.

Exercise | Q V. 2. | Page 77

Assertion: Incident ray is directed towards the centre of curvature of spherical mirror. After reflection it retraces its path.

Reason: Angle of incidence (i) = Angle of reflection (r) = 0°

• If both assertion and reason are true and reason is the correct explanation.

• If both assertion and reason are true and reason is not the correct explanation.

• If assertion is true but reason is false.

• If assertion is false but reason is true.

#### Answer very briefly.

Exercise | Q VI. 1. | Page 78

According to cartesion sign convention, which mirror and which lens has negative focal length?

Exercise | Q VI. 2. | Page 78

Name the mirror(s) that can give (i) an erect and enlarged image, (ii) same sized, inverted image

Exercise | Q VI. 3. | Page 78

If an object is placed at the focus of a concave mirror, where is the image formed?

Exercise | Q VI. 4. | Page 78

Why does a ray of light bend when it travels from one medium to another?

Exercise | Q VI. 5. | Page 78

What is the speed of light in vacuum?

Exercise | Q VI. 6. | Page 77

Concave mirrors are used by dentists to examine teeth. Why?

Exercise | Q VII. 1. | Page 78
1. Complete the diagram to show how a concave mirror forms the image of the object.
2. What is the nature of the image? Exercise | Q VII. 2. | Page 78

Pick out the concave and convex mirrors from the following and tabulate them.

Rear-view mirror, Dentist’s mirror, Torchlight mirror, Mirrors in shopping malls, Make-up mirror.

Exercise | Q VII. 3. | Page 78

State the direction of incident ray which after reflection from a spherical mirror retraces its path. Give reason for your answer.

Exercise | Q VII. 4. | Page 78

What is meant by magnification? Write its expression. What is its sign for real image and virtual image?

Exercise | Q VII. 5. | Page 78

Write the spherical mirror formula and explain the meaning of each symbol used in it.

#### Answer in detail.

Exercise | Q VIII. 1. | Page 78

a) Draw ray diagrams to show how the image is formed using a concave mirror, when the position of object is:

1. at C
2. between C and F
3. between F and P of the mirror.

b) Mention the position and nature of image in each case.

Exercise | Q VIII. 2. | Page 78

Explain with diagrams how refraction of incident light takes place from

1. rarer to denser medium
2. denser to rarer medium
3. normal to the surface separating the two media.
Exercise | Q IX. 1. | Page 78

Numerical problem.

A concave mirror produces three times magnified real image of an object placed at 7 cm in front of it. Where is the image located? (Ans: 21 cm in front of the mirror)

Exercise | Q IX. 2. | Page 78

Numerical problem.

Light enters from air into a glass plate having refractive index 1.5. What is the speed of light in glass? (Ans: 2 × 108 ms–1)

Exercise | Q IX. 3. | Page 78

Numerical problems.

The speed of light in water is 2.25 × 108 ms–1. If the speed of light in vacuum is 3 × 108 ms–1, calculate the refractive index of water.

Exercise | Q X. 1. | Page 78

Higher Order Thinking Skills.

Light ray emerges from water into air. Draw a ray diagram indicating the change in its path in water.

Exercise | Q X. 2. | Page 78

Higher Order Thinking Skills.

When a ray of light passes from air into glass, is the angle of refraction greater than or less than the angle of incidence?

Exercise | Q X. 3. | Page 78

Higher Order Thinking Skill.

What do you conclude about the speed of light in diamond. if the refractive index of diamond is 2.41?

## Chapter 6: Light

Exercise ## Tamil Nadu Board Samacheer Kalvi solutions for Class 9th Science Answers Guide chapter 6 - Light

Tamil Nadu Board Samacheer Kalvi solutions for Class 9th Science Answers Guide chapter 6 (Light) include all questions with solution and detail explanation. This will clear students doubts about any question and improve application skills while preparing for board exams. The detailed, step-by-step solutions will help you understand the concepts better and clear your confusions, if any. Shaalaa.com has the Tamil Nadu Board of Secondary Education Class 9th Science Answers Guide solutions in a manner that help students grasp basic concepts better and faster.

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Concepts covered in Class 9th Science Answers Guide chapter 6 Light are Formation of Image by Reflection: Real and Virtual Image, Spherical Mirrors, Reflection of Light, Law of Reflection of Light, Concave Mirror, Sign Convention for Reflection by Spherical Mirrors, Mirror Equation/Formula, Linear Magnification (M) Due to Spherical Mirrors, Speed of Light, Refraction of Light, Refraction of Light from a Plane Transparent Surface, Law of Refraction of Light, Total Internal Reflection, Convex Mirror, Light, Lateral Inversion, Images Formed by Spherical Mirrors, Rules for the Construction of Image Formed by a Spherical Mirror, Image Formation by Concave Mirror, Image Formation by Convex Mirror.

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