Samacheer Kalvi solutions for Science [English] Class 9 TN Board chapter 6 - Light [Latest edition]

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

______ is used as reflectors in torchlight.

We can create enlarged, virtual images with ______.

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

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

The speed of light is maximum in ______.

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

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

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.

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

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

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.

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

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

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

The mirror used in search light is ______.

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

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

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

Match the following.

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.

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°

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

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

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

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

What is the speed of light in vacuum?

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

1. Complete the diagram to show how a concave mirror forms the image of the object.
2. What is the nature of the image?

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.

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

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

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

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.

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.

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)

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)

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.

Higher Order Thinking Skills. 

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

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?

Higher Order Thinking Skill.

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