Q2 of 14 Page 289

Here are the shadows of some 3-D objects, when seen under the lamp of an overhead projector. Identify the solid(s) that match each shadow. (There may be multiple answers for these!)

(i) Spherical, (ii) Cube, (iii) Pyramid, (iv)Cuboid.


(i) Sphere is formed by rotating a circle in 3D.


(ii) Cube shadows to a square in 2D.


(iii) A triangle is formed by image of a pyramid.


(iv) A cuboid is 3D representation of rectangle.


More from this chapter

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5

Give (i) an oblique sketch and (ii) an isometric sketch for each of the following:

(a) A cuboid of dimensions 5 cm, 3 cm and 2 cm. (Is your sketch unique?)


(b) A cube with an edge 4 cm long.

 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

 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).

 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.