The apparent weight of wood floating on water it it weight 100 g in air is :

The apparent weight of an object is the weight of the object in air minus the buoyant force acting on it.

The buoyant force is the weight of the fluid displaced by the object. In this case, the fluid is water and the object is wood.

Since the wood is floating, it displaces a volume of water equal to its own volume. The weight of this volume of water is equal to the buoyant force.

The weight of the wood in air is given as 100 g.

The weight of the wood in water (its apparent weight) is its weight in air minus the buoyant force.

Since the wood is floating, the buoyant force is equal to the weight of the wood in air.

Therefore, the apparent weight of the wood in water is 100 g - 100 g = 0 g.

So, the apparent weight of the wood floating on water is 0 g.