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NCERT Solutions Curiosity Chapter 11 .3 Light through Transparent, Translucent, and Opaque Materials — Activity 11.3: Let us experiment

Book page 156 & 15711 Updated on2026-09-05

Q1.
List the materials of the objects in Table 11.1 and classify them into transparent, translucent, and opaque.
Answer

Here is Table 11.1 completed. The last two rows are objects you may add from your own classroom.

MaterialTransparent / Translucent / OpaqueLight will pass fully / partially / not at all
My predictionMy observation
CardboardOpaqueNot at allNot at all
PaperTranslucent (thin paper) / Opaque (thick paper)PartiallyPartially — a dim glow is seen through thin paper
Glass (clear window glass)TransparentFullyFully — the bright spot stays on the screen
Tracing paperTranslucentPartiallyPartially — a blurred patch of light
Thick clothOpaqueNot at allNot at all
Polythene sheet (thin, colourless)Transparent to translucentFullyAlmost fully; slightly hazy
Steel plate / wooden scaleOpaqueNot at allNot at all
Tip: Judge a material by how clearly you can see through it — sharp view = transparent, blurred glow = translucent, nothing at all = opaque.
Q2.
Predict what will happen if you hold an object in front of the light coming out of the torch. Would you continue to see the spot of light on the screen? Note your prediction in Table 11.1.
Answer

The prediction should follow from the kind of material:

  • Glass or clear plastic — yes, the spot of light will still be seen, almost as bright as before.
  • Tracing paper or thin cloth — the spot will still be there but dim and blurred.
  • Cardboard, thick cloth or a steel plate — no, the spot will disappear and a dark patch (a shadow) will take its place.
Tip: A prediction is not a guess made after the event. Write it in the table before you put the object in the beam — that is what makes the next step a real test.
Q3.
Was your observation the same as your prediction? What conclusions could you draw?
Answer

For most objects the observation matches the prediction. A surprise or two is normal — thin paper often lets more light through than expected, and a coloured transparent sheet lets light through but changes its colour.

The conclusions are:

Transparent materials → light passes almost completely
Translucent materials → light passes partially
Opaque materials → light does not pass at all
Why it happens: In a transparent material the light finds a clear straight way through. In a translucent material the light is scattered again and again inside, so only a part of it comes out and it comes out spread in all directions — which is why the patch looks dim and blurred. In an opaque material the light is completely absorbed or reflected at the surface, so none of it gets through.
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