Question

A liquid drop having surface energy 'E' is spread into 512 droplets of the same size. The final surface energy of the droplets is ______.

पर्याय

• 2E

• 4E

• 8E

• 12E

Answer 1

A liquid drop having surface energy 'E' is spread into 512 droplets of the same size. The final surface energy of the droplets is 8E.

Explanation:

The Surface area of drop, A₁ = 4πR²

Surface area of 512 droplets, A₂ = 512 (4πr²)

R = (512)^1/3 r ⇒ R = 8r

∴ A₂ = `(512(4πr)^2)/64`

∴ A₂ = 8(4πr²)

Surface energy ∝ Area

∴ `"E"_2/"E"_1 = "A"_2/"A"_1 = (8(4πr)^2)/(4π"r"^2)`

∴ E₂ = 8E₁ = 8E  .......(∵ E₁ = E)