Question

The surface tension of a liquid is 5 n/m. if a film is held on a ring of area 0.02 m2 its surface energy is about

Answer 1

Hello buddy,

◆ Answer-
E = 0.4 J

◆ Explaination-
# Given-
T = 5 N/m
A = 0.02 m^2

# Solution-
As soap film will be formed at both sides of ring,
Area = 2A

Surface energy is calculated by -
Surface energy = Surface tension × area
E = T × 2A
E = 5 × 2 × 0.02
E = 0.2 J

Surface energy is therefore 0.2 J.

Hope this helps you...

Answer 2

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•GIVEN:

→Surface Tension (T)=5

→Area of liquid film=0.02

•TO FIND:

Surface Energy of ring of given area.

→As the ring is to be made out of a film it will have 2 free surfaces.

→E=T×2A

→E=5×2×0.02

→E=0.2

•Thus the it's surface energy is 0.02