Question

Take a straight tube that can be bent easily. As shown in the figure, place a burning candle on a stand, and look at it through the tube. Then bend the tube and look at the candle again. What do you see?

Answer 1

When we look at the burning candle through the straight tube, we can see the candle flame clearly.

When the tube is bent, the candle flame cannot be seen through it.

This shows that light travels in a straight line. Since light cannot bend along the curved tube, it does not reach our eyes when the tube is bent.