NCERT Solutions for Class 7 Science Chapter 15 Light

# NCERT Solutions for Class 7 Science Chapter 15 Light

Edited By Vishal kumar | Updated on Sep 20, 2023 12:17 PM IST

## NCERT Solutions for Class 7 Science Chapter 15- Access and Download Free PDF

NCERT Solutions for Class 7 Science Chapter 15 Light: Solution for chapter 15 science class 7th are the part of NCERT Solutions for Class 7 Science. Learning through activities makes a chapter interesting. The chapter light has many activities which makes it very easy to understand. Along with these activities if you have NCERT solutions of C lass 7 Science chapter 15 Light in hand, then scoring good marks in the exam is an easy thing. The NCERT solutions for Class 7 Science chapter 15 Light give an explanation for 13 questions and two of them are simple numerical problems. While going through this chapter you will come across concepts like the applications of concave mirror and lens, how the image is visible in a plane mirror, what are the properties of image formed by a plane mirror, convex and concave mirror and lens etc.

The NCERT solutions for Class 7 Science chapter 15 Light helps to understand these concepts well. While learning a chapter, first of all, try to answer all the questions by yourself. Then, if you need any help then refer to NCERT Solutions for the respective chapters. Students are recommended to go through NCERT Solutions for Class 7 to score high marks in their examination.

**As per the CBSE Syllabus 2023-24, this chapter has been renumbered as Chapter 11 in Class 7 Science.

Free download class 7 science chapter 15 question answer PDF for CBSE exam.

## NCERT Solutions For Class 7 Science Chapter 15 Light: Exercise Solutions

(a) virtual image. Only real images can be obtained on the screen.

(b) mirror.

(c) plane.

(d) real image. On these type of images can be obtained on the screen.

(e) concave lens. As virtual images cannot be obtained on the screen.

(a) False. As the size of the image formed is smaller.

(b) True.

(c) True as the concave mirror gives a real and enlarged image.

(d) False. Real images can be obtained on screens whereas virtual images cannot be.

(e) False. As the nature of the image is decided by the distance between the object and mirror.

 Column I Column II (a) A plane mirror (i) Used as a magnifying glass. (b) A convex mirror (ii) Can form an image of objects spread over a large area. (c) A convex lens (iii) Used by dentists to see an enlarged image of teeth. (d) A concave mirror (iv) The image is always inverted and magnified. (e) A concave lens (v) The image is erect and of the same size as the object. (vi) The image is erect and smaller in size than the object.

(a) The image formed by a plane mirror is erect and of the same size.

(b) The image formed by a concave mirror is inverted and magnified. Also, they can form images of objects spread over a large area.

(c) A convex lens is used as magnifying glasses.

(d) A concave mirror is used to see enlarged images.

(e) The image formed by a concave lens is erect and smaller in size.

An image formed by a plane mirror is:-

(i) virtual

(ii) erect

(iii) of the same size

The letter which has vertical symmetry will have this property.

In English alphabets, we have A, H, I, M, O, T, U, W, X, X, Y that appears exactly like itself in the plane mirror.

The image which can be screened (or obtained on screen) is known as a virtual image.

For e.g. in case of a candle which is placed in front of a plane mirror, we observe a virtual image of the candle formed behind the mirror.

The basic difference between the two are given below:-

(i) In the case of a convex lens, it converges the falling rays of light whereas in the case of the concave lens the rays diverge.

(ii) A concave lens has thick edges and is thin at the middle but the convex lens is thick at the middle.

The side-view mirror in a vehicle is a convex mirror for getting wider view of the rear.

To see an enlarged image of teeth, dentists use a concave mirror.

A concave mirror can form real images which can be obtained on the screen. The nature of the image formed by these mirrors depends upon the distance between the object and mirror.

The images formed by a concave lens is always virtual, magnified and erect in nature.

The correct answer is a concave mirror. The image formed by a concave mirror can be both virtual or real depending on the position of the object. Also, the image obtained is magnified.

We are given the distance between the mirror and his image = 4 m

Now, if David moves 1 m towards the mirror, then the distance is = 4 − 1 = 3 m

Hence, the distance between David and his image is = 3 + 3 = 6 m.

We are given that the speed of the car is 2 m/s which implies, the car is approaching the truck with a speed of 2 m/s.

Hence the speed at which the image of the truck appears to approach the driver will be: 2 $\times$ 2 = 4 m/s

The NCERT class 7th science chapter 15 question answer consist of a total of thirteen questions that include multiple-choice, matching, and true/false type questions. The solutions, created by the experts at Careers360, are in accordance with the latest CBSE syllabus. The solutions are explained in detail and in easy-to-understand language. Students can download the PDF version of the solutions and use them offline for their convenience.

### Chapter-wise NCERT Solutions of Class 7 Science

 Chapter 1 Nutrition in Plants Chapter 2 Nutrition in Animals Chapter 3 Fibre to Fabric Chapter 4 Heat Chapter 5 Acids, Bases and Salts Chapter 6 Physical and Chemical Changes Chapter 7 Weather, Climate and Adaptations of Animals to Climate Chapter 8 Winds, storms and cyclones Chapter 9 Soil Chapter 10 Respiration in Organisms Chapter 11 Transportation in Animals and Plants Chapter 12 Reproduction in Plants Chapter 13 Motion and Time Chapter 14 Electric Current and its Effects Chapter 15 Light Chapter 16 Water: A Precious Resource Chapter 17 Forests: Our Lifeline Chapter 18 Wastewater Story

## Class 7 Science Chapter 15 NCERT Solutions: Important Formulas and Points

#### Light

• Light is a form of energy that enables us to see objects around us.

• It travels in straight lines and at a very high speed, approximately 3 × 10^8 meters per second in a vacuum.

#### Sources of Light:

Natural Sources: The Sun is the primary natural source of light. It emits light due to nuclear reactions.

Artificial Sources: Artificial sources of light include electric bulbs, candles, and lamps, which produce light through various means.

#### Reflection and Laws of Reflection

Reflection of light is the process by which light waves encounter a surface and bounce back in the same medium, obeying certain rules. It occurs when light rays strike an object or surface that does not absorb the light but instead sends it back. This phenomenon is responsible for our ability to see objects, as the reflected light enters our eyes.

Laws of Reflection

• The incident ray (incoming ray), the reflected ray (outgoing ray), and the normal (a line perpendicular to the surface) all lie in the same plane.

• The angle of incidence (the angle between the incident ray and the normal) is equal to the angle of reflection (the angle between the reflected ray and the normal).

Mathematically, the law of reflection can be expressed as:

Angle of Incidence (i) = Angle of Reflection (r)

## Lenses

#### Refraction

• Refraction is when light bends as it moves from one material to another.

• After refraction, we see an apparent object, which may not be in the same place as the actual object due to the bending of light.

#### Image Formation by Lenses

• Convex lenses (like a magnifying glass) can form real, inverted, and smaller images. When objects are very close, the image may be erect, virtual, and larger.

• Concave lenses (used in cameras and binoculars) create virtual, erect, and smaller images.

#### Dispersion of White Light

• White light, like sunlight, is made up of seven colours: violet, indigo, blue, green, yellow, orange, and red.

• Passing white light through a prism or seeing it on a CD separates it into these colours, creating a rainbow.

• This separation of white light into its component colours is called dispersion.

Light Class 7 Science Chapter 15-Topics

• Light Travels Along a Straight Line
• Reflection of Light
• Right or Left!
• Playing With Spherical Mirrors
• Images Formed by Lenses
• Sunlight — White or Coloured?

Importance of NCERT Solutions for Class 7 Science Chapter 15 Light:

• A tool like NCERT solutions for Class 7 Science chapter 15 Light helps students to solve homework problems
• With the help of NCERT solutions of C lass 7 Science chapter 15 Light students can perform well in Class 7 exams
• NCERT solutions for Class 7 Science chapter 15 Light covers questions related to all the concepts studied in the chapter.
• The concepts studied in this chapter are revised in the coming classes also.

## key Features of Class 7 Science Chapter 15 NCERT Solutions

1. Comprehensive Coverage: The NCERT class 7 science chapter 15 question answer cover all the topics and concepts presented in Chapter 15 of the Class 7 Science textbook, providing a thorough understanding of light-related phenomena.

2. Detailed Explanations: The class 7 light ncert solutions offer clear and detailed explanations for each question and exercise, making complex concepts easy to grasp for students.

3. Step-by-Step Approach: The light class 7 questions and answers follow a step-by-step approach, guiding students on how to solve problems and answer questions effectively.

4. Use of Simple Language: The solutions are presented in simple language suitable for Class 7 students, making it easier for them to understand and apply the concepts.

5. Practice Questions: The science chapter 15 class 7 often include practice questions and examples to reinforce the learning of key principles.

6. Exam Preparation: The class 7 science ch 15 question answer are designed to help students prepare for exams by offering a structured approach to answering questions and solving problems.

7. Clarity and Accuracy: The light class 7 ncert solutions are accurate and aligned with the content provided in the NCERT textbook, ensuring that students receive reliable information.

8. Accessible Format: NCERT light class 7 questions and answers can be accessed in various formats, including print, digital, and online resources, making them convenient for students to use for homework and revision.

These features make light class 7 solutions an invaluable resource for students to master the concepts related to light and its properties.

### Frequently Asked Questions (FAQs)

1. Whether the Class 7 Science Chapter 15 Light is useful in higher studies ?

Yes, this chapter is very important for higher studies in the field of science and physics. Also, we will study in Class 10 Science NCERT syllabus and Class 12 Physics NCERT book.

2. What is light?

Light is a form of energy that is detected by the human eye. It is an electromagnetic wave.

3. Write the name natural source of light.

The natural sources of light are; lightning, stars, the sun, etc

4. What are the topics covered in NCERT Class Science chapter 15?

Here are the topics covered in NCERT Class 7 Science chapter 15

•   Light Travels Along a Straight Line
•    Reflection of Light
•    Right or Left!
•    Playing With Spherical Mirrors
•    Images Formed by Lenses
•    Sunlight — White or Coloured?
5. How many questions consist of class 7 science ch 15 question answer?

Class 7 Science Chapter 15 question answer consists of a total of thirteen questions which include multiple-choice, matching, and true/false type questions.

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Get answers from students and experts

A block of mass 0.50 kg is moving with a speed of 2.00 ms-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

 Option 1) Option 2) Option 3) Option 4)

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times.  Assume that the potential energy lost each time he lowers the mass is dissipated.  How much fat will he use up considering the work done only when the weight is lifted up ?  Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate.  Take g = 9.8 ms−2 :

 Option 1) 2.45×10−3 kg Option 2)  6.45×10−3 kg Option 3)  9.89×10−3 kg Option 4) 12.89×10−3 kg

An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

 Option 1) Option 2) Option 3) Option 4)

A particle is projected at 600   to the horizontal with a kinetic energy . The kinetic energy at the highest point

 Option 1) Option 2) Option 3) Option 4)

In the reaction,

 Option 1)   at STP  is produced for every mole   consumed Option 2)   is consumed for ever      produced Option 3) is produced regardless of temperature and pressure for every mole Al that reacts Option 4) at STP is produced for every mole Al that reacts .

How many moles of magnesium phosphate, will contain 0.25 mole of oxygen atoms?

 Option 1) 0.02 Option 2) 3.125 × 10-2 Option 3) 1.25 × 10-2 Option 4) 2.5 × 10-2

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

 Option 1) decrease twice Option 2) increase two fold Option 3) remain unchanged Option 4) be a function of the molecular mass of the substance.

With increase of temperature, which of these changes?

 Option 1) Molality Option 2) Weight fraction of solute Option 3) Fraction of solute present in water Option 4) Mole fraction.

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

 Option 1) twice that in 60 g carbon Option 2) 6.023 × 1022 Option 3) half that in 8 g He Option 4) 558.5 × 6.023 × 1023

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

 Option 1) less than 3 Option 2) more than 3 but less than 6 Option 3) more than 6 but less than 9 Option 4) more than 9