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Exercise 15.3
Question 1:
What cross-sections do you get when you give a:
(i) vertical cut (ii) horizontal cut to the following solids?
(a) A brick
(b) A round apple
(c) A die
(d) A circular pipe
(e) An ice-cream cone.
Answer 1:
S.No. | Name of article | Figure | Vertical cut | Horizontal cut |
(a) | A brick | ![]() | ![]() | ![]() |
(b) | A round apple | ![]() | ![]() | ![]() |
(c) | A die | ![]() | ![]() | ![]() |
(d) | A circular pipe | ![]() | ![]() | ![]() |
(e) | An ice-cream cone | ![]() | ![]() | ![]() |
Exercise 15.4
Question 1:
A bulb is kept burning just right above the following solids. Name the shape of the shadows obtained in each case. Attempt to give a rough sketch of the shadow.
(You may try to experiment first and then answer these questions).
Answer 1:
S.No. | Object | Shadow | Shape's name |
(i) | A ball | ![]() | Circle |
(ii) | A cylindrical pipe | ![]() | Line |
(iii) | A book | ![]() | Rectangle |
Question 2:
Here are the shadows of some 3-D objects, when seen under the lamp of the overhead projector. Identify the solid (s) that match each shadow.
(There may be multiple answers for these!)
Answer 2:
S. No. | Shadow | Shape's Name | 3-D objects |
(i) | ![]() | Circle | Chapatti, Football, Disc, Plate etc. |
(ii) | ![]() | Square | Die, Square paper sheet, cubical magic box, Chalk box etc. |
(iii) | ![]() | Triangle | Ice-cream cone, Birthday cap, etc. |
(iv) | ![]() | Rectangle | Geometry box, Book, Table etc. |
Question 3:
Examine if the following are true statements:
(i) The cube can cast a shadow in the shape of a rectangle.
(ii) The cube can cast a shadow in the shape of a hexagon.
Answer 3:
(i) True
(ii) False
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