Question

Water applies upthrust on an iron ball when it is completely immersed. Now, the iron ball is taken out and heated and then again it is completely immersed into the water. Compare the upthrust in the initial and final situation.

• A. Initial upthrust will be more than the final.
• B. In both the cases upthrust will be same.
• C. Final upthrust will be more than the initial.
• D. Cannot be determined

Answer 1

The correct option is C

Final upthrust will be more than the initial.

The iron ball expands on heating, hence the volume of the iron ball increases and when this iron ball is submerged into the water it displaces more water. So, the upthrust applied by the water on the iron ball will increase as it is dependent on the amount of the water displaced.