A wire of length $10 \mathrm{~cm}$ is gently placed horizontally on the surface of water having surface…

A wire of length $10 \mathrm{~cm}$ is gently placed horizontally on the surface of water having surface tension of $75 \times 10^{3} \mathrm{~N} / \mathrm{m}$. What force is required to just pull up the wire from the water surface?
  1. $15 \times 10^{-2} \mathrm{~N}$
  2. $7 \cdot 5 \times 10^{-2} \mathrm{~N}$
  3. $1 \cdot 5 \times 10^{-2} \mathrm{~N}$
  4. $75 \times 10^{-2} \mathrm{~N}$

Solution

$F=2(T L)=2 \times 75 \times 10^{-3} \times 10 \times 10^{-2}$ $=150 \times 10^{-4}=1.5 \times 10^{-2} \mathrm{~N}$

Asked in: MHT CET 2020 (12 Oct Shift 1)

Practice more Mechanical Properties of Fluids questions on Aicharya