Page 148 - Science Class 07
P. 148

4.  The images formed by a plane mirror are always _____________         inverted.
                  5.  A _____________     mirror has its surface curved outward like the outer surface of a sphere.

                  6.  The central point of a spherical mirror is its _____________    and it is denoted by P.
              C.  Write True or False.
                  1.  Moon gives us light, but is not a natural source of light.

                  2.  A luminous object may be ar ficial or man-made.
                  3.  The rays of the sun takes about eight minutes and 20 seconds to reach the surface
                      of the earth.
                  4.  Reflec on of light is regular from smooth bright surface.
                  5.  Real images can be obtained on a screen whereas unreal image cannot.
              D.  Very short answer ques ons.
                  1.  Name any three ar ficial sources of light.
                  2.  What do you mean by luminous bodies?
                  3.  What is the beam of light?
                  4.  What is reflec on of light?
                  5.  What is the centre of curvature?
                  6.  What is lateral inversion?
                  7.  Write any three proper es of real images.
              E.  Short answer ques ons.
                  1.  Differen ate between natural and ar ficial sources of light.
                  2.  How can you say that light travels in a straight line?
                  3.  If the distance between the source of light and a object is 750,000 km, in how much  me
                      the light will reach the object?
                  4.  What are the two laws of reflec on?
                  5.  Why the word AMBULANCE is wri en laterally inverted on ambulance vehicle?
              F.   Long answer ques ons.
                  1.   What is the advantage of Kaleidoscope?
                  2.   What is radius of curvature?
                  3.   Write the feature of image, formed by concave mirror, of an object that is placed between
                      its centre of curvature and focus?
                  4.   What type of mirror is used in the headlight of vehicle and why?
                  5.  Write the uses of convex mirror.
             Project
             Project ActivityActivityActivity
             Project
             Project Activity
              A.   Make a model of periscope with the help of hard cardboard and plane mirror.
              B.   Visit a science gallery and see your distorted and funny images in the mirror fi ed there. Try to
                  know the kind of mirrors used there.

              C.  Make a model of kaleidoscope with the help of plane glass and coloured pieces of bangles by
                  covering it with black paper.
             HO
             HO
             HOTSTSTS
             HOTS
              There is a big and a small plane mirror. Compare the images of the same object formed by these
              two mirrors.
              148                                                                                           Science-7
   143   144   145   146   147   148   149   150   151   152   153