The hair of a paint brush forms a fine tip when it is:
AHeld under water
BPressed on paper
CTaken out of water
DKept fully dry
Answer & Solution
Correct answer: C. Taken out of water
1. Dry hair does not cling, and hair dipped in water does not either.
2. The film of liquid left behind pulls the hair together.
3. So the fine tip forms when the brush is taken out of water.
_Source: NCERT Class 11 Physics Part II, Chapter 10, Mechanical Properties of Fluids._
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