Question

Vook
10. A frame made of metallic wire enclosing a surface area is covered with
a soap film.If the area of the frame of the metallic wire is increased by 10%
energy of the soap film will be changed by"​

Answer 1

Explanation:

Area of one side of frame =A

But metallic wire frame having soap film has two surfaces.

Thus total surface area of the frame =2A

Energy of soap film, E=2AT (where T is the surface tension of soap film)

Now the surface area of one side is reduced to half i.e A

′

=

2

A

∴ E

′

=2A

′

T=2T×

2

A

=AT

Percentage change in energy =

E

E−E

′

×100=

2AT

2AT−AT

×100=50 %