Consider the following statements distinguishing Luminous and Illuminated objects: 1. The Sun and a candle flame are examples of illuminated objects. 2. The Moon is an example of an illuminated object. 3. Illuminated objects emit their own light. Which of the statements given above is/are correct?

The correct option is (b). Explanation In optics, objects are classified based on their ability to emit light. Luminous objects are sources that generate and emit their own light. Illuminated (or non-luminous) objects do not emit light themselves; they become visible only when light from a luminous source falls on them and is reflected to the observer's eyes. Statement-wise Analysis: - Statement 1 is Incorrect. The Sun and a candle flame generate their own light through nuclear fusion and chemical combustion, respectively. Therefore, they are classified as luminous objects, not illuminated objects. - Statement 2 is Correct. The Moon does not produce its own light. It shines because it reflects the sunlight falling on its surface. Consequently, it is an example of an illuminated object. - Statement 3 is Incorrect. By definition, illuminated objects do not emit their own light. They only reflect light originating from other sources. It is luminous objects that emit their own light. Key Takeaway: The primary distinction in optics regarding visibility is that luminous objects are light sources (e.g., Sun, stars, bulbs), while illuminated objects are visible solely due to the reflection of light (e.g., Moon, planets, wood).

Consider the following statements distinguishing Luminous and… - NCERT Class 8 Science MCQ

NCERT Class 8 Science — Chapter 4: Light

mcqeasy

Consider the following statements distinguishing Luminous and Illuminated objects:

The Sun and a candle flame are examples of illuminated objects.
The Moon is an example of an illuminated object.
Illuminated objects emit their own light.

Which of the statements given above is/are correct?

NCERT textbook question

From NCERT Science - class 8 · Page 169

Options

A1 only
B2 only
C1 and 3 only
D1, 2 and 3

Did you get this right?

Solution

The correct option is (b).

Explanation

In optics, objects are classified based on their ability to emit light. Luminous objects are sources that generate and emit their own light. Illuminated (or non-luminous) objects do not emit light themselves; they become visible only when light from a luminous source falls on them and is reflected to the observer's eyes.

Statement-wise Analysis:

Statement 1 is Incorrect. The Sun and a candle flame generate their own light through nuclear fusion and chemical combustion, respectively. Therefore, they are classified as luminous objects, not illuminated objects.
Statement 2 is Correct. The Moon does not produce its own light. It shines because it reflects the sunlight falling on its surface. Consequently, it is an example of an illuminated object.
Statement 3 is Incorrect. By definition, illuminated objects do not emit their own light. They only reflect light originating from other sources. It is luminous objects that emit their own light.

Key Takeaway:

The primary distinction in optics regarding visibility is that luminous objects are light sources (e.g., Sun, stars, bulbs), while illuminated objects are visible solely due to the reflection of light (e.g., Moon, planets, wood).

Your note

More from Chapter 4: Light

With reference to the Periscope, consider the following statements: 1. It works on the principle of multiple reflections. 2. It uses two plane mirrors arranged at right angles to each other. 3. It allows viewing of objects that are not directly in the line of sight. Which of the statements given above are correct?

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With reference to image formation by a plane mirror, consider the following statements: 1. The image formed cannot be obtained on a screen. 2. The image appears at a greater distance behind the mirror than the object is in front. 3. The image undergoes lateral inversion. Which of the statements given above are correct?

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Consider the following statements about the image formed by a plane mirror: 1. It is inverted vertically. 2. It is of the same size as the object. 3. It appears to be at the same distance behind the mirror as the object is in front. Which of the statements given above is/are correct?

easy

In the context of the reflection of light, what does the term 'angle of incidence' refer to?

easy

With reference to the eye's ability to see, consider the following statements: 1. A normal eye can clearly see distant objects as well as objects nearby. 2. The minimum distance for distinct vision is constant at 50 cm for all ages. 3. In old age, eyesight may become foggy due to the eye lens becoming cloudy. Which of the statements given above is/are correct?

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