Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: When you squeeze one end of a tube to get toothpaste out from the other end, Pascal's principle is observed.
Reason R: A change in the pressure applied to an enclosed incompressible fluid is transmitted undiminished to every portion of the fluid and to the walls of its container.
In the light of the above statements, choose the most appropriate answer from the options given below

Solution

Physics sir · 4 steps

Your thumb pushes on one spot, yet paste comes out at the far end: that is Pascal's law at work.

1. Check Reason R. R is the exact statement of Pascal's law: a change in pressure applied to an enclosed incompressible fluid reaches every part of the fluid and the container walls undiminished. So R is correct.
2. Check Assertion A. The toothpaste is a fluid enclosed in the tube. Squeezing one end raises the pressure there, and that extra pressure is passed through the whole paste to the open nozzle, where the paste flows out. So A is correct.
3. Link A and R. The paste comes out at the far end only because the pressure from your squeeze is transmitted undiminished along the tube. That transmission is exactly what R describes, so R explains A.
4. So. Both statements are correct and R is the correct explanation of A, which is option (d). The "A and B" in that option is a typo for "A and R".

The idea to keep. Whenever a push at one point of an enclosed fluid shows up somewhere else (toothpaste, hydraulic lift, car brakes), think Pascal's law: the pressure change spreads undiminished everywhere.

Answer from the NTA final answer key. Solution by PrepWiser.