if you keep the revs up and the water isn't too deep - not much. If the engine is running slow, water can back up into the exahsut system and hit your catalytic converter, which is hot and may crack due to the change in temperature. if the water is very high, don't go near it as your engine will not be waterproofed, electrics may fail and air inlet will fill with water if you don't have a snorkel fitted.
youll proberly drown lol
the light bounces of the water
no
A car can hydroplane, essentially glide on water
Dry them.
water flows through it
It changes and stuff.
Stop and back out. Find another route around the water.
True
step slowly on the brakes
The light will bend as it passes through.
When carbon dioxide is passed through lime water it will turn milky.
temperature decreases