Read the passage below and answer the following question <br><br>
Take an empty plastic bottle. Close the mouth of the bottle with an airtight stopper. Put it in a bucket filled with water. We can see that the bottle floats.<br><br>
Push the bottle into the water. We can feel an upward push. If we try to push it further down, it will be difficult to push it deeper and deeper. Now release the bottle. It bounces back to the surface.The force due to the gravitational attraction of the earth acts on the bottle in the downward direction. So the bottle is pulled downwards. But the water exerts an upward force on the bottle. Thus the bottle is pushed upwards. Also the weight of an object is the force due to gravitational attraction of the earth. When the bottle is immersed, the upward force exerted by the bottle by the water on the bottle is greater than its weight. Therefore it rises up when released.
<br><br>To keep the bottle completely immersed the upward force on the bottle due to water should be balanced. This can be achieved by an externally applied force acting downwards. This force must be at least equal to the difference between the upward force and the weight of the bottle. <br><br>
QUESTION : Which of the statement is not true? <br>
1. An object floats if its density is lesser than that of the liquid in which it is immersed <br>
2. The density of a substance is mass per unit area <br>
3. The weight of an object is due to the gravitational pull on it <br>
4. The downward force exerted by the liquid is called buoyancy
