Correct Option
The correct option is (b) 2 only.
Explanation
The phenomenon of flotation is governed by the principle of buoyancy and relative density. Whether an object floats or sinks in a fluid depends on the relationship between the density of the object and the density of the fluid. This is a direct application of Archimedes' Principle, often studied in the context of gravitation and fluid mechanics.
Statement-wise Analysis
- Statement 1 is Incorrect.
If an object has a density greater than that of water, the gravitational force (weight) acting downwards is greater than the buoyant force (upthrust) exerted by the water when the object is fully submerged. Consequently, the object will sink.
- Statement 2 is Correct.
If an object has a density less than that of water, the buoyant force acting on it is sufficient to balance its weight before it is completely submerged. Therefore, the object will float on the surface of the water.
- Statement 3 is Incorrect.
The standard density of pure water at 4°C is approximately 1000 kg m-3 (or 1 g cm-3). The value stated, 100 kg m-3, is factually incorrect.
Key Takeaway: An object floats if its density is lower than the fluid's density and sinks if it is higher. The standard density of water is 1000 kg m-3.