A drop of olive oil of radius 1 mm spreads into a circular film of dia

1.	A drop of olive oil of radius 1 mm spreads into a circular film of diameter 40 cm on a water surface. Estimate the size of an oil molecule.
Answer» Volume of the oil is conserved. Radius of oil drop = R = 1 mm Radius of the oil film on the water surface is r = 20 cm The thickness of the oil film formed represents the size of the oil molecule. (4/3)πR³ = πr² × size of a molecule ⇒ Size of a molecule = (4/3) x (R³/r²) = (4/3) x ((1 x 10^-3)³)/(20 x 10^-2)²) = 0.33 × 10^-7 m

A drop of olive oil of radius 1 mm spreads into a circular film of diameter 40 cm on a water surface. Estimate the size of an oil molecule.

Answer»

Volume of the oil is conserved. Radius of oil drop = R = 1 mm

Radius of the oil film on the water surface is r = 20 cm

The thickness of the oil film formed represents the size of the oil molecule.

(4/3)πR³ = πr² × size of a molecule

⇒ Size of a molecule = (4/3) x (R³/r²)

= (4/3) x ((1 x 10^-3)³)/(20 x 10^-2)²)

= 0.33 × 10^-7 m