Class 7 Science - WEST-BENGAL
Light: Shadows and Reflections
In the West Bengal Board (WBBSE) Class 7 Science chapter 'Light: Shadows and Reflections', students explore the fascinating nature of light and how it travels. You will learn the difference between luminous and non-luminous objects, and classify materials as transparent, translucent, or opaque based on how light passes through them. The chapter also explains the fascinating science behind shadow formation and how smooth surfaces create clear reflections through mirrors. Mastering these concepts is essential for scoring well in your school exams and understanding everyday optical phenomena.
Start Learning FreeKey Concepts
Luminous Objects
Objects that emit their own light, such as the Sun, electric bulbs, and glowing stars.
Transparent, Translucent, and Opaque Materials
Transparent materials allow light to pass through completely, translucent materials allow partial light, and opaque materials block light entirely.
Shadow Formation
A dark patch formed when an opaque object blocks the path of light, requiring a source of light, an opaque object, and a screen.
Rectilinear Propagation of Light
The scientific principle that light always travels in a straight line.
Reflection of Light
The bouncing back of light rays from a smooth, shiny surface like a plane mirror, which helps us see images.
Important Formulas
Board Exam Info
In West Bengal (WBBSE) Class 7 final examinations, this chapter typically carries around 6 to 8 marks. Questions usually include short-answer questions (SAQ), fill-in-the-blanks, differences between transparent and opaque objects, and drawing diagrams of shadow formation or pinhole cameras.
Frequently Asked Questions
Why is a shadow always black even if the object is colored?
A shadow is simply an absence of light. When an opaque object blocks light rays, no light reaches the screen behind it, creating a dark patch regardless of the object's color.
What is the difference between a shadow and an image?
A shadow only shows the dark outline or shape of an object without any details or colors. An image formed by a mirror shows all the details, colors, and features of the object.
Why do we see a laterally inverted image in a plane mirror?
A plane mirror reverses the sides horizontally, meaning your right side appears as the left side in the mirror reflection, which is called lateral inversion.
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