When a solid body is partially or completely immersed in a fluid, the fluid exerts an upward force on the body. The magnitude of the force is equal to 1. the mass of the body 2. the weight of the displaced fluid by the body Which of the above is/are correct ?

According to Archimedes' Principle, when a solid body is partially or completely immersed in a fluid, it experiences an upward force known as the buoyant force or upthrust [2]. This principle states that the magnitude of this upward force is exactly equal to the weight of the fluid displaced by the body [1]. While the mass of the body remains constant regardless of its environment, the buoyant force depends specifically on the weight of the displaced fluid, which is calculated as the product of the displaced fluid's mass and gravity [2]. If the weight of the displaced fluid is less than the weight of the object, the object will sink; if it is equal, the object floats [3]. Therefore, statement 1 is incorrect because the force is not equal to the mass of the body itself, but rather the weight of the fluid it displaces [4].

Sources

1. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > A step further > p. 76
2. [2] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > Snapshots > p. 77
3. [3] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 6: Pressure, Winds, Storms, and Cyclones > Activity 6.4: Let us perform > p. 87
4. [4] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > A step further > p. 75