vlim:Verysuperkiasu:[quote=\"ngbrdad\"]
How did you manage to see the question ?
based on my son's memory....he drew out the pic for me.
light source--->small square cardboard---->metal ball--->bigger square cardbord but same height as the metal ball--->screen (all these are in side view profile). His answer is a square - (the square blocks the metal ball since they are of the same height).
then it should be circle right..as firstly the small square cardboard ball not going to have any effect..though the 3 rd object which is a square cardboard, has the same height as the ball, it is within shadow of the cirle metal ball..
< O X... :roll:[/quote]
my dd says in front of the light source there is something like a wall with a hole in it so when she drew the line starting from the hole, the metal ball's shadow will be cast on the screen.Her answer is the circle.