Light And General Terms Class-7th Goyal Brothers ICSE Physics Solutions Ch-4 Unit-1

Light And General Terms Used In Understanding Light Class-7th Goyal Brothers ICSE Physics Solutions Chapter-6(Light Energy) Unit-1(Light And General Terms Used In Understanding Light). We Provide Step by Step Answers of Objectives, Fill in the blanks, Match the following, True/False, Incorrect and Correct, Question Type answers of Chapter-4(Light Energy) Unit-1(Light And General Terms Used In Understanding Light). Visit official Website  CISCE  for detail information about ICSE Board Class-7.

Light And General Terms Used In Understanding Light ICSE Class-7th Goyal Brothers Physics Solutions Chapter-4 Unit-1

Board ICSE
Class 7th
Subject Physics
Book Name Goyal Brothers
Chapter-4 Light Energy
Unit-1 Light And General Terms Used In Understanding Light
Topic Solution of exercise questions
Session 2023-24

OBJECTIVE QUESTIONS

Light And General Terms Used In Understanding Light ICSE Class-7th Goyal Brothers

Physics Solutions Chapter-4 Unit-1

Que: A. Fill in the blanks spaces by choosing the correct words from the list given below :

List : opaque, shadow, transparent, luminous, energy

1. All bodies which emit light energy by themselves are called luminous bodies.

2. Light is a form of energy.

3. The materials through which things can be seen are called transparent materials.

4. The materials through which things cannot be seen are called opaque materials.

5. A region of darkness or partial light is called shadow.

Que: B. Statements given below are incorrect. Write the correct statements :

Question: 1. Stars are non-luminous body.

Answer: Stars are luminous body.

Question: 2. Air is an opaque body.

Answer: Air is always transparent.

Question: 3. Moon is a luminous body.

Answer: Moon is a non-luminous body.

Question: 4. The path along which the light energy travels in a given direction is called a beam of light.

Answer: The path along which the light energy travels in a given direction is called a ray of light.

Question: 5. When a ray of light starting from a point travels in various directions, the collection of such rays is called convergent beam of light.

Answer: When a ray of light starting from a point travels in various directions, the collection of such rays is called divergent beam of light.

Que: C. Write ‘True’ or ‘False’ for the following statements :

Answer:

Statements True/False
1. Planets are luminous bodies. F
2. Light is invisible, but causes the sensation of vision. T
3. The dust particles in the path of light becomes visible when light falls on them. T
4. Clear water is an opaque medium. F
5. Air is a transparent medium. T

Que: D. Tick (√) the most appropriate answer :

1. Which is not a non-luminous body?

(a) Earth

(b) Moon

(c) Glowworm

(d) Wood

Answer: option (c) Glowworm is correct.

2. Which is not a luminous body?

(a) Sun

(b) Star

(c) Planet

(d) Glowworm

Answer: option (c) Planet is correct.

3. Which is a transparent body?

(a) Muddy water

(b) Oiled paper

(c) Stone

(d) Clear glass

Answer: option (d) Clear glass is correct.

4. Which is not an opaque body?

(a) Stone

(b) Wood

(c) Clear water

(d) Coal

Answer: option (c) Clear water is correct.

5. Which is not a translucent medium?

(a) Butter paper

(b) Diamond

(c) Ground glass

(d) Oiled paper

Answer: option (a) Butter paper is correct.

Que: E. Match the statements is Column A, with those in Column B :

Column A

Column B

1. A body having light energy of its own. (a) Beam of light
2. A straight line path along which light energy travels. (b) Glowworm
3. A collection of large number of rays of light. (c) Opaque
4. Anything through which light cannot pass. (d) Ray of light
5. An insect which emits light in the dark. (e) Luminous body

Answer:

Column A

Column B

1. A body having light energy of its own. (a) Luminous body
2. A straight line path along which light energy travels. (b) Ray of light
3. A collection of large number of rays of light. (c) Beam of light
4. Anything through which light cannot pass. (d) Opaque
5. An insect which emits light in the dark. (e) Glowworm

STUDY QUESTIONS

Light And General Terms Used In Understanding Light ICSE Class-7th Goyal Brothers

Physics Solutions Chapter-4 Unit-1

Question: 1. (a) What is meant by light energy?

Answer: Light energy is a kind of kinetic energy with the ability to make types of light visible to human eyes. Light is defined as a form of electromagnetic radiation emitted by hot objects like lasers, bulbs, and the sun.

(b) How do we seen an object?

Answer: Light from a source like the Sun, falls on the object. The object reflects light in all possible directions. The reflected light from the object reaches our eyes. Our brain receives the information from the eyes making us see the object.

 Question: 2. (a) By giving three examples define natural sources of light.

Answer: Three examples define natural sources of light:

  1. A natural source of light is light that occurs naturally without the involvement of humans.
  2. Natural sources of light can come from either an object or a living species.
  3. Sun, stars, lightning, jellyfish, fireflies, glowworms, bush fires, angler fish, and other natural light sources are examples.

(b) By giving three example define artificial sources of light.

Answer: Bulb, candles, torches are some of the examples of artificial sources of light.

Question: 3. (a) Define luminous object. Give examples also.

Answer: Objects that emit or give out light or energy of their own are referred to as luminous objects. The sensation of light is caused by luminous objects. These objects are visible because the light is emitted by them on their own. For example, the Sun, stars, electric bulbs, torches, tube lights, candles, and so on.

(b) Define non-luminous object and give examples.

Answer: A non-luminous object is one that does not produce its own light, although it can still reflect light from other sources. The Moon is an example of a non-luminous object; we can only see the Moon because it reflects light from the Sun.

Question: 4. Why are the moon and the planets considered as non-luminous objects?

Answer: In our solar system, the sun is the only luminous object. All of the planets and moons reflect light (the light from the sun bounces off them) and absorb light but they don’t emit light, so we say they are non-luminous.

Question: 5. By giving three examples define the following terms :

(a) Transparent material

Answer: Air, water, clear glass

(b) Translucent material

Answer: oily paper, tissue, some plastics,

(c) Opaque material

Answer: Plastic, wood, stone

Question: 6. By drawing neat diagrams define the following :

(a) Ray of light

Answer: The light traveling in any one direction in a straight line is called a ray of light. A group of light rays given out from a source is called a beam of light.

(b) Parallel beam of light

Answer: When Rays from a distant point source travel parallel to each other in a particular direction, it forms a parallel Light Beam.

(c) Convergent beam of light

Answer: When light rays from different points constantly keep coming closer together and finally meet at a point, then the light beam is known as a convergent beam of light.

(d) Divergent beam of light

Answer: Light rays from a point source of light travel in all directions, moving away with time. Such a beam of light is called a divergent beam of light. Light emitted from a bulb, a candle or a lighthouse are examples of a divergent beam.

Question: 7. (a) Define rectilinear propagation of light.

Answer: Rectilinear propagation of light:

  1. Rectilinear~ means straight.
  2. Propagation~ means travelling of light.

The property of light travelling in a straight lines in a homogenous transparent medium is known as rectilinear propagation of light.

Light does not bend. This is the reason why you are unable to see around a corner.

(b) What is meant by a shadow?

Answer: A shadow is a dark area where light from a light source is blocked by an opaque object. It occupies all of the three-dimensional volume behind an object with light in front of it.

— : end of Light And General Terms Used In Understanding Light ICSE Class-7th Goyal Brothers Physics Solutions Ch-4 Unit-1:–-

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