The volume of a sealed packet is 1 liter and its mass is 800 g. The packet is first put inside the water with a density of 1 g cm-3 and then in another liid B with a density of 1.5 g cm- 3. Then which one of the following statements holds true?

To determine if the packet floats or sinks, we must calculate its density and compare it to the fluids. Density is defined as mass per unit volume [3]. The packet has a mass of 800 g and a volume of 1 liter, which is equivalent to 1000 cm3. Thus, the packet's density is 800 g / 1000 cm3 = 0.8 g/cm3. According to Archimedes' Principle and the laws of buoyancy, an object floats if its density is less than the fluid's density and sinks if it is greater [1]. Since the packet's density (0.8 g/cm3) is less than the density of water (1 g/cm3), it will float in water. Similarly, since 0.8 g/cm3 is less than the density of liquid B (1.5 g/cm3), it will also float in liquid B. However, the standard physics logic for this specific problem type indicates it sinks if its density exceeds the fluid; here, it is lighter than both, making it float in both.

Sources

1. [3] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 9: The Amazing World of Solutes, Solvents, and Solutions > Note Safety First > p. 146
2. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > A step further > p. 76