Question

According to Archimedes’ principle the buoyant force is equal to:
A. weight of liquid displaced
B. weight of object immersed in liquid
C. net force applied on object
D. none of the above

Answer 1

Hint: Recall the statement for the Archimedes’ principle. Using the statement given in this principle, check the necessary condition for the object partially or completely immersed in a fluid to be in equilibrium. This condition gives the relation between buoyant force acting on the object in the fluid and the weight of the liquid displaced.

Complete answer:
According to Archimedes’ principle, the buoyant force is equal to weight of the liquid displaced and not equal to weight of the object immersed in the liquid or net force applied on the object.Hence, the options B and C are incorrect.

The Archimedes’ principle states that the buoyant force or upward thrust exerted by the fluid on the partially or fully submerged object in the fluid in the upward direction is equal to the weight of the fluid which is displaced by the partially or fully submerged body in the fluid and this buoyant force acts in the upward direction passing through centre of mass of the displaced fluid.Thus, according to Archimedes’ principle, the buoyant force is equal to weight of the liquid displaced.

Hence, the correct option is A.

Note: The students may think that the weight of the liquid displaced is always equal to weight of the object immersed in the liquid. So, option B should be correct. But the students should keep in mind that the weight of the liquid displaced is equal to the weight of the portion of the object immersed in the liquid and not equal to weight of the whole object. Hence, option B is incorrect.