Question

a drop of olive oil of radius 0.30mm spreads into a nearly circular film of radius 12 cm onn the water surface . estimate the molecular size of olive oil

Answer 1

Here is the answer---

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Given ⇒

Radius of the one drop olive oil = 0.3 mm.

= 0.03 cm.

We know, the drop is generally spherical i shape,

Thus volume of the drop = (4/3)π r³

= 4π × 0.000009

= 0.000036 cm³

As per as the Question,Water Surface is circular in shape,

Radius of the Water Surface(r) =12 cm.

∴ Area = π r².

= π × (12)².

= 144 π cm².

∵ Molecular Size = \frac{Volume of one drop}{Area of Water Surface}MolecularSize=

AreaofWaterSurface

Volumeofonedrop

⇒ Molecular Size = \frac{0.000036 \pi}{144 \pi }MolecularSize=

144π

0.000036π

⇒ Molecular Size = 0.25 × 10⁻⁶

= 2.5 × 10⁻⁷ m.

∴ Molecular Size of the one drop of the olive oil is 2.5 × 10⁻⁷ m.