Q. Which of the following situations are explained by Archimedes' principle:

1. A submarine adjusting depth in sea
2. A hot-air balloon rising in the sky
3. A swimmer floating on salty water

Select the correct option from the codes given below:
Answer: 1, 2 & 3
Notes: Archimedes' principle is applicable to both liquids and gases. Submarines adjust buoyancy based on fluid displacement (1), hot-air balloons rise due to buoyant force in air (2), and salty water increases buoyancy, aiding swimmers to float (3). All three situations are direct applications of Archimedes' principle.