IMO Practice Test — Light & Shadows
6 Questions • 12 min • Olympiad level
12:00
Question 1 of 6
hard
Stars are natural light sources, but planets are not, because planets only…
Spin fast
Are small
Are cold
Reflect light from a star
Explanation: Planets reflect starlight; they do not make their own.
Question 2 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 3 of 6
hard
Two torches shining on one object from different sides can make…
A mirror
No shadow ever
A rainbow
Two shadows
Explanation: Each light makes its own shadow, so two form.
Question 4 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 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
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.