Question

you are given three pieces of card with holes in them, a piece of cotton thread and a candle. Explain how you could use this apparatus to show that light travels in a straight line
please answer

Answer 1

Answer:

keep the cards in series with holes in straight line and keep an opaque surface at one end show they are straight with thread and place a candle at the other end

Explanation:

light will flow at straight line though the holes at the opaque surface