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Selina solutions for Class 7 Physics chapter 4 - Light Energy

Selina Concise Physics - Middle School for Class 7 (2018-19 Session)

Selina Selina Concise Physics - Middle School Class 7 (2018-19 Session) Chapter 4: Light Energy

Chapter 4: Light Energy solutions [Page 0]

Write true or false

The image formed by a plane mirror is real

Write true or false

When a light ray is reflected from a wall, the angle of incidence is not equal to the angle of reflection.

Write true or false

The image of the right hand in a plane mirror looks like that of a left hand.

Write true or false

The image formed by a plane mirror is upright.

Write true or false

The image formed by a plane mirror can be obtained on a screen.

Write true or false

The objects are seen around us due to irregular reflection of light.

Write true or false

The speed of light in vacuum is 3 × 108 ms-1.

Write true or false

A rose appears red in light of all the colours.

Write true or false

A black paper absorbs light of all the colours and reflects none.

Write true or false

The primary colours are red, blue and green.

Fill in the blank

Angle of incidence = ......................

Fill in the blank

The incident ray, the reflected ray and the normal lie in one .........

Fill in the blank

The image formed by a plane mirror is at a distance behind the mirror as .................

Fill in the blank

The image formed by a plane mirror is erect and .............

Fill in the blank

We are able to see the objects around us due to ..........., reflection.

Fill in the blank

A ............. image cannot be obtained on a screen.

Fill in the blank

A plane mirror .............. reflect 100 percent light falling on it.

Fill in the blank

The colour of an opaque object is the colour of light which it ................

Fill in the blank

Magenta, cyan and yellow are the.................colours.

Match the following

 (a). A light ray passes             from air to glass (1) . speeds up (b). A light ray passes             from glass to water (2). reflacts red light (c). Virtual image (3). primary colours (d). Red rose (4). plane mirror (e). Red , green , and               blue (5). slows down

Select the correct alternative

A man standing in front of a plane mirror finds his image to be at a distance of 6 metre from himself. The distance of man from the mirror is

1. 6 m
2. 3 m
3. 2 m
4. 12 m

Select the correct alternative

The angle between the incident ray and the ray reflected from the plane mirror is 70°. The angle of incidence will be :

1. 70°
2. 30°
3. 35°
4. 90

Select the correct alternative

The image formed by a plane mirror is

1. virtual and inverted
2. virtual and of same size
3. real and inverted
4. real and of same size

Select the correct alternative

The angle of incidence on a plane mirror is 30°.The angle of reflection will be:

1. 30°
2. 60°
3. 15°

Select the correct alternative

The angle of incidence on a plane mirror is 30°. The angle between the incident ray and the reflected ray is

1. 30°
2. 15°
3. 60°
4. 90°

Select the correct alternative

The property due to which a light ray striking a surface is returned back into the same medium is called

1. refraction
2. reflex action
3. reflection
4. regression

Select the correct alternative

The speed of light is maximum in

1. glass
2. water
3. air
4. wood

Select the correct alternative

A red rose is seen in green light. It will appear.

1. red
2. blue
3. yellow
4. black

Select the correct alternative

The primary colours are

1. Red, Blue and Yellow
2. Magenta, Yellow and Cyan
3. Red, Blue and Cyan
4. Blue, Green and Red

Chapter 4: Light Energy solutions [Page 0]

What do you mean by the term reflection of light ?

How is a plane mirror made ?

Explain the following terms:
Incident ray, Reflected ray, Angle of incidence, Angle of reflection, Normal.

Draw a diagram showing the reflection of a light ray from a plane mirror. Label on it the incident ray, the reflected ray, the normal, the angle of incidence i and the angle of reflection r.

State the two laws of reflection of light.

Describe an experiment to verify the laws of reflection of light. Ans. Laws of reflection.

A ray of light falls normally on a plane mirror. What is the angle of incidence ?

Draw a diagram to show the reflection of a light ray incident normally on a plane mirror.

The diagram in Fig. shows an incident ray AO and the reflected ray OB from a plane mirror. The angle AOB is 30°. Draw normal on the plane mirror at the point O and find :

In the following diagrams, measure and write the angle of incidence and draw the reflected ray in given case. In the following diagrams, measure and write the angle of incidence and draw the reflected ray in each case. In the following diagrams, measure and write the angle of incidence and draw the reflected ray in each case. The diagram in fig. shows an incident ray AO and the normal ON on a plane mirror. Draw the reflected ray. State the law you use to draw the direction of the reflected ray. The following diagram shows an incident ray AO and the normal ON on a plane mirror. Find the angle of incidence and angle of reflection. State in words, how do you find the location of image of an object formed by a plane mirror.

Draw a ray diagram showing the formation of image of a point object by a plane mirror.

The following diagram shows a point object O placed in front of a plane mirror. Take two rays from the point O and show how the image of O is formed and seen by the eye. State four characteristics of the image formed by a plane mirror.

How is the position of image formed by a plane mirror related to the position of the object ?

You are standing at a distance 2 metre from a plane mirror.

What is the distance of your image from the mirror ?

You are standing at a distance 2 metre from a plane mirror.

What is the distance between you and your image ?

What is meant by lateral inversion of an image in a plane mirror ? Explain it with the help of a diagram.

Wirte down the letter C and I as seen in a plane mirror.

What is irregular reflection ? Give an example.

How do we see objects around us ?

State two uses of a plane mirror.

Can light travel in vacuum ?

State the speed of light in (a) air, (b) glass.

State whether light slows down or speeds up in the following cases :

Light going from air to glass.

State whether light slows down or speeds up in the following cases :

Light going from glass to water.

State whether light slows down or speeds up in the following cases :

Light going from water to air.

What are the primary colours ? Name the three primary colours.

What are the secondary colours ? Name the three secondary colours.

Fill in the blanks with the appropriate colour

Blue + ………… = Cyan

Fill in the blanks with the appropriate colour

Red + Blue + …………. = Vhite

Fill in the blanks with the appropriate colour

Red + Blue = …………

Fill in the blanks with the appropriate colour

Green + Red = …………

The leaves appear green when seen in white light. Give a reason.

A rose appears red in white light. How will it appear in
(i) green light, (ii) red light ? Give a reason for your answer for each.

Why does a piece of paper appear white in sunlight ? How would you expect it to appear when viewed in red light?

A piece of paper appears black in sunlight. What will be it£ colour when seen in red light ?

Chapter 4: Light Energy

Selina Selina Concise Physics - Middle School Class 7 (2018-19 Session) Selina solutions for Class 7 Physics chapter 4 - Light Energy

Selina solutions for Class 7 Physics chapter 4 (Light Energy) 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 CISCE Selina Concise Physics - Middle School for Class 7 (2018-19 Session) solutions in a manner that help students grasp basic concepts better and faster.

Further, we at Shaalaa.com are providing such solutions so that students can prepare for written exams. Selina textbook solutions can be a core help for self-study and acts as a perfect self-help guidance for students.

Concepts covered in Class 7 Physics chapter 4 Light Energy are Concept of Reflection, Terms Related to Reflection:Normal, Plane, Point of Incidence, Angle of Incidence, Angle of Reflection, Laws of Reflection, Plane Mirror - Uses, Plane Mirror - Ray Diagram (No Mention of Virtual Image), Plane Mirror - Characteristics of the Image Formed (Lateral Inversion, Same Size, Distance is Preserved)., Speed of Light (3 X 10 8 M/S)., Primary Colours (RGB), Formation of Secondary Colours by Colour Addition., Appearance of Colour of an Object (Based on Reflection and Absorption), Colour Subtraction, Concept of Light Energy.

Using Selina Class 7 solutions Light Energy exercise by students are an easy way to prepare for the exams, as they involve solutions arranged chapter-wise also page wise. The questions involved in Selina Solutions are important questions that can be asked in the final exam. Maximum students of CISCE Class 7 prefer Selina Textbook Solutions to score more in exam.

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