IMO Practice Test — Light & Shadows
6 Questions • 12 min • Olympiad level
12:00
Question 1 of 6
medium
Why can we see the Moon shining at night if it makes no light?
It has bulbs
It burns gas
It reflects sunlight to us
It is a star
Explanation: The Moon shines by reflecting the Sun's light.
Question 2 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.
Question 3 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 4 of 6
hard
Car drivers use mirrors mainly to…
Store fuel
Make light
Cool the car
See vehicles behind them
Explanation: Mirrors reflect the view behind so drivers can see it.
Question 5 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 6 of 6
hard
In a dark cinema we can still see the screen because the screen sends ___ to our eyes.
Sound
Light
Heat
Air
Explanation: We see the screen because light reaches our eyes.