A wooden block with a coin placed on its top, floats in water as shown in Fig.10.3. The distance l and h are shown in the figure. After some time, the coin falls into the water. Then

A. l decreases.

B. h decreases.

C. l increases.

D. h increase.

When the coin is on the top of the block, it displaces volume V₁ of water whose weight is equal to the weight of the coin. Whereas, in the second case, the coin displaces the volume of water V₂ whose volume is equal to the volume of the coin.

According to case 1,

Here,

So,

This means in the second case less volume is displaced and hence h decreases.

As the coin falls into the water, total weight of the block-coin system decreases and less water is displaced than before and hence I decreases.