Room light:
On
Off
Lens:
Converging(+)
Diverging(−)
Chalk dust:
On
Off
Screen or eye:
Screen
Eye
Object:
Arrow
Arrow Light
Light Beam
Rays
Zoom Screen
Smaller (−);
Larger (+)
cm
10
10
20
30
40
50
60
70
80
90
100
110
120
130
20.0
90.0
50.0
Ray Box
Image on screen
A lens will not collect enough light reflecting off the arrow
to form an image bright enough to be seen on the screen.
Use your eye or switch to an object that emits light.
