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MHT CET · Physics · Mechanical Properties of Fluids

A water drop is divided into 8 equal droplets. The pressure difference between the inner and outer side of the big drop will be

  1. A same as the smaller droplet.
  2. B half of that for smaller droplet
  3. C \(\left(\frac{1}{4}\right)^{\text {th }}\) of that for smaller droplet.
  4. D twice that for smaller droplet
Verified Solution

Answer & Solution

Correct Answer

(B) half of that for smaller droplet

Step-by-step Solution

Detailed explanation

Volume of 8 smaller drops \(=\) Volume of the bigger drop
\(\begin{array}{ll}
& \Rightarrow 8 \times \frac{4}{3} \pi r^3=\frac{4 \pi}{3} R^3 \\
\therefore & 2 r=R \text { or } r=\frac{R}{2}
\end{array}\)
\(\begin{aligned} & \text { Excess pressure }\left(P_i-P_o\right)=\frac{2 T}{r} \\ & \Delta P_s=\frac{T}{2 r}, \Delta P_B=\frac{T}{2 R} \\ \therefore \quad & \frac{\Delta P_B}{\Delta P_S}=\frac{r}{R}=\frac{1}{2} \\ & \Rightarrow \Delta P_B=\frac{\Delta P_S}{2}\end{aligned}\)