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    5.  A dentist uses a concave mirror to examine       7.  During a solar eclipse, students use a pinhole
                         a  patient’s  tooth.  The tooth  is  placed  very    camera to observe the Sun. They notice that
                         close  to the  mirror, within its  focal length.     the image of the Sun on the screen is inverted
                         The dentist notices that the image is upright        and smaller than the actual  Sun. Which
                         and magnified,  making  examination  easier.         principle  of light  explains  this  observation?
                         Which principle explains this observation?                                   (Abstract Thinking)

                                                  (Abstract Thinking)
                                                                                    (a)   Light bends  around corners,
                                                                                       making the image smaller.

                                                                                    (b)   Light travels in straight lines,
                                                                                       forming  a  real, inverted  and
                                                                                       smaller image through the pinhole.

                                                                                    (c)   The pinhole increases the intensity
                                                                                       of light, making the image smaller.

                                (a)   Concave  mirrors always  produce              (d)   The pinhole blocks most of the light,
                                   inverted images.                                    producing a faint shadow.

                                (b)  Concave    mirrors     produce        8.  In  a cinema  hall,  a projector  projects  light
                                   magnified, erect images when the           onto a screen. When a person walks in front
                                   object is within the focal length.         of the beam, a their shadow appears on the
                                                                              screen.
                                (c)   Plane  mirrors produce  magnified
                                   images at all distances.

                                (d)   Convex  mirrors are used  to
                                   magnify objects.
                      6.  A  kaleidoscope  is  made  using  three  plane
                         mirrors inclined  at  60°  to  each  other.
                         When a child looks inside, she sees multiple
                         symmetrical  patterns  formed  by  colored
                         glass pieces.                                        Why is the shadow sharp and clear?
                         Which  principle  of reflection  explains  the                                  (Decomposition)
                         repeated patterns?     (Pattern recognition)
                                                                                    (a)   The person is  translucent  and
                                (a)  Multiple  reflections  between
                                                                                       bends light.
                                   inclined plane mirrors
                                                                                    (b)   The  person is opaque and blocks
                                (b)   Random scattering of light by glass              light travelling in straight lines.
                                   pieces

                                                                                    (c)   The projector enlarges the person’s
                               (c)  Refraction  of   light   through
                                   transparent glass                                   image on the screen.
                                                                                    (d)   The screen absorbs all light falling
                                (d)   Absorption  of light by opaque
                                   surfaces                                            on it.

                     88        Computational Thinking-7 (Science)

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