Respuesta :
Answer:
0.06563 N/m
The percentage difference between the calculated and tabulated value of water surface tension is 9.78%
Explanation:
Solution:-
- Surface tension is the ability of any fluid to resist any external force due to cohesive nature of the fluid molecules.
- Surface tension ( γ ) is defined as the force imparted per unit length on the fluid.
              γ = F / L
Where,
       F: Force
       L: The length over which force is felt
- The mass ( M = 3.78g ) of ( n = 100 ) water droplets are carefully burette. We need to determine the mass of a single droplet as follows:
             m = M / n
             m = 3.78 / 100
            m = 0.0378 g    Â
- Assuming the distance over which the drop falls is negligible and resistive forces are negligible. Then the only force acting on the droplet is due to gravity ( Weight of the droplet ):
            F = m*g
            F = 0.0378*9.81*10^-3
            F = 0.000370818 N   Â
- The length over which the force is felt can be modeled into a circular patch with diameter ( d ) = equal to the diameter ( d ) of the single water drop. The length ( L ) is defined as the circumference of the patch:
            L = π*d
            L = π*( 0.0018 )
            L = 0.00565 m
- The surface tension would be:
            γ = F / L
            γ = 0.000370818 / 0.00565
            γ = 0.06563 N / m
- The given value of water's surface tension is given as follows:
            γa = 0.07275 N/m
- To compare the two values we will determine the percentage difference between the value evaluated  and tabulated value as follows:
          % [tex]diff = \frac{0.07275- 0.06563}{0.07275} * 100 \\\\diff = 9.78 \\\\[/tex]
- The percentage difference ( 9.78% ) between the two values is within  practical limits of 10%. Hence, the calculated can be accepted.
