CBSE Class 7 Science Question 1 of 17

Light Shadows and Reflections — Question 1

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1
Question
What happens when an opaque object blocks the path of light? (Page 157)
Answer

When light falls on an opaque object, it cannot pass through, and a dark region called a shadow appears on the screen or surface behind the object.


Source: This question is from Light Shadows and Reflections, Science — Class 7, CBSE Board.

Key Concepts Covered

This question tests your understanding of the following concepts from the chapter Light Shadows and Reflections: Happens, Opaque, Object, Blocks, Path, Light. These are fundamental topics in Science that students are expected to master as part of the CBSE Class 7 curriculum.

A thorough understanding of these concepts will help you answer similar questions confidently in your CBSE examinations. These topics are frequently tested in both objective and subjective sections of Science papers. We recommend revising the relevant section of your textbook alongside practising these solved examples to build a strong foundation.

How to Approach This Question

Read the question carefully and identify what is being asked. Break down complex questions into smaller parts. Use the terminology and concepts discussed in this chapter. Structure your answer logically — begin with a definition or key statement, then provide supporting details. Review your answer to ensure it addresses all parts of the question completely.

Key Points to Remember

  • Read the question carefully and identify all parts before answering.
  • Use the terminology specific to this subject and chapter.
  • Review the textbook content for this chapter before attempting questions.
  • Practice writing concise, well-structured answers within time limits.

Practice more questions from Light Shadows and Reflections — Science, Class 7 CBSE

Chapter 11: Light

Reflection follows two laws: angle of incidence equals angle of reflection, and all rays are in the same plane. Plane mirror images are virtual, erect, same size, and laterally inverted. Concave mirrors converge light (used in torches, dentist mirrors). Convex mirrors diverge light (used in rear-view mirrors). Dispersion splits white light into VIBGYOR through a prism. Rainbows are natural dispersion by water droplets.

Theme: Physics | Difficulty: Age-appropriate for Class VII

Key Formulas & Equations

Formula / Equation When to Use
Law 1: Angle of incidence = Angle of reflection (∠i = ∠r)First law of reflection
VIBGYOR: Violet, Indigo, Blue, Green, Yellow, Orange, RedSpectrum colours in order

Must-Know Concepts

  • Two laws of reflection: ∠i = ∠r; same plane
  • Plane mirror: virtual, erect, same size, laterally inverted, equal distance behind
  • Lateral inversion: left-right swap (AMBULANCE written in reverse)
  • Concave mirror: converges light, uses = torch, headlight, dentist, solar cooker
  • Convex mirror: diverges light, wider view, uses = rear-view mirror
  • Real image: on screen; Virtual image: cannot be on screen
  • Dispersion: white light through prism gives VIBGYOR spectrum

Common Mistakes to Avoid

  • Thinking plane mirror image is real — it is virtual
  • Confusing lateral inversion with upside-down
  • Thinking white light is pure — it is a mixture of 7 colours

Scoring Tips

  • Draw ray diagrams with incident ray, normal, reflected ray, and angles
  • List 5 properties of plane mirror image
  • Compare concave and convex mirrors with uses