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Gap-fill exercise

  
Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!
1. Those lenses which feel thinner in the middle than at the edges are lenses.
2. We should not look at the sun through lens.
3. If one half of convex lens is covered with a black paper, then the convex lens will produce the of the object.
4. Image formed by a concave lens is always , and .
5. Image formed by a convex lens is mostly , and except when object is very close.
6. Concave lens is used in spectacles to correct .
7. Convex lens is used in spectacles to correct .
8. In the formation of a rainbow, the suspended in the atmosphere act a tiny prism.
9. Uneven surfaces show reflection.
10. The inner surface of the reflector of a torch acts as a mirror.