Properties of Matter 4 Question 8
10. If the radius of the opening of the dropper is $r$, the vertical force due to the surface tension on the drop of radius $R$ (assuming $r«R$ ) is
(a) $2 \pi r T$
(b) $2 \pi R T$
(c) $\frac{2 \pi r^2 T}{R}$
(d) $\frac{2 \pi R^2 T}{r}$
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Answer:
Correct Answer: 10. (c)
Solution:
- Vertical force due to surface tension,
$$ F _v=F \sin \theta=(T 2 \pi r)(r / R)=\frac{2 \pi r^{2} T}{R} $$
$\therefore$ Correct option is (c).
