MCQ
Force necessary to pull a circular plate of $5\, cm$ radius from water surface for which surface tension is $75\, dynes/cm,$ is
- A$30\,dyne$
- B$60 \,dynes$
- C$750 \,dynes$
- ✓$750 \,\pi \,dynes$
✓
Answer
Correct option: D.
$750 \,\pi \,dynes$
d
(d) The total length of the circular plate on which the force will act $ = 2\pi R$
(d) The total length of the circular plate on which the force will act $ = 2\pi R$
Force to pull $ = 2\pi RT = 2 \times \pi \times 5 \times 75 = 750\pi \, dynes$
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