Question

A wooden block, with a coin placed on its top, floats in water as shown in figure. the distance $l$ and $h$ are shown there. After some time the coin falls into the water. Then

• A. $l$ decreases and $h$ increases
• B. $l$ increases and $h$ decreases
• C. both $l$ and $h$ increases
• D. both $l$ and $h$ decreases

Answer 1

The correct option is D both $l$ and $h$ decreases

Hint: Consider the fact that density of coin is very high in comparison of water and wood.

Density of coin is more so it was applying considerable force on wood before falling in water.
But once it'll fall, wood can't apply same force alone so wood will come a little up as result $l$ will decrease.

When coin falls in water, wood goes up, so displaced volume decreases and as coin has higher density so its volume is less and hence it doesn't displace liquid that much. As a result $h$ will also decrease.