IMO Practice Test — Light & Shadows
6 Questions • 12 min • Olympiad level
12:00
Question 1 of 6
hard
Why are windows made of transparent glass and not opaque wood?
To let light into the room
To keep light out
To make shadows
To stay warm
Explanation: Transparent glass lets daylight into the room.
Question 2 of 6
hard
A shopkeeper sees a red apple as red because the apple sends ___ light to the eyes.
Green
Blue
Red
No
Explanation: The apple reflects red light, so we see it as red.
Question 3 of 6
hard
A glowing firefly and the hot Sun are both natural light sources, but the firefly is special because its light is…
Cool, not hot
Very hot
Man-made
A reflection
Explanation: A firefly makes cool light without much heat.
Question 4 of 6
hard
The word AMBULANCE is written backwards on the front of vans so that drivers ahead read it correctly in their…
Window
Mirror
Shadow
Map
Explanation: A mirror flips it back to normal for the driver ahead.
Question 5 of 6
hard
Coloured cellophane is transparent but tinted; looking through red cellophane makes the world look…
Reddish
Black
Invisible
Louder
Explanation: Tinted transparent sheets colour the light passing through.
Question 6 of 6
hard
A sundial tells the time using the moving…
Sound of birds
Colour of the sky
Shadow of a pointer
Wind
Explanation: A sundial reads time from a shadow that moves with the Sun.