Class 7 Science - ODISHA
Light: Shadows and Reflections
The chapter 'Light: Shadows and Reflections' in Class 7 Science introduces students to the fascinating behavior of light. Students learn how light travels in a straight line and what happens when opaque objects block its path, leading to the formation of shadows. The chapter also explores how mirrors change the direction of light through reflection and how images are formed. This is a crucial topic for Odisha BSE board exams as it forms the foundation for advanced optics in higher classes, frequently appearing in both objective and short-answer questions.
Start Learning FreeKey Concepts
Rectilinear Propagation of Light
Light travels in a straight line, which is why opaque objects block it to form dark patches called shadows.
Transparent, Translucent, and Opaque Objects
Transparent objects let light pass through completely, translucent objects allow partial light, and opaque objects block light entirely.
Shadow Formation
A shadow is formed when an opaque object comes in the path of light, requiring a source of light, an opaque object, and a screen.
Reflection of Light
The bouncing back of light rays from a shiny or polished surface, like a plane mirror, is called reflection.
Lateral Inversion
The phenomenon where the right side of an object appears as the left side and vice versa in a mirror image.
Important Formulas
Board Exam Info
Under the Odisha BSE board, this chapter typically carries around 4 to 6 marks. Common question types include defining terms like reflection and lateral inversion, drawing diagrams of shadow formation, and explaining why shadows are formed.
Frequently Asked Questions
Why is a shadow always black even if the object has a color?
A shadow is simply an absence of light. When an opaque object blocks light, no light reaches the screen in that area, creating a dark patch regardless of the object's color.
What is lateral inversion?
Lateral inversion is the sideways reversal of an image in a plane mirror, where your left hand appears as your right hand in the reflection.
Can we see a shadow in the dark?
No, a shadow cannot be formed or seen in complete darkness because shadow formation requires a source of light.
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