Question

A thin wire is bent in the form of a ring of diameter 3.0cm .The ring is placed horizontally on the surface of soap solution and then raised up slowly .how much upward force is necessary to break the vertical film formed between the ring and the solution?

Answer 1

d = diameter of the ring of wire = 3 cm = 0.03 m

r = radius of ring of wire = diameter/2 = d/2 = 0.03/2 = 0.015  m

k = surface tension of soap solution = 0.05 N/m

L = length of ring = circumference of circle = 2πr = 2 (3.14) (0.015) = 0.0942 m

Upward force is given as

F = 2 k L

inserting the values in the above equation

F = 2(0.05) (0.0942)

F = 9.42 x 10⁻³ N

Answer 2

Answer:

5.652 ×10^-3

Explanation:

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