Question

13. A square frame of side 2 cm is dipped in a liquid.
A membrane is formed when taken out, force
acting on the frame. (Surface tension of liquid is
2.5 N/m) is nearly equal to
(2) Zero
(4) 0.41 N
(1) 1.25 N
(3) 0.21 N​

Answer 1

Force  acting on the frame is 0.2 N which is nearly 0.21 N, So option D is correct.

Explanation:

1. Side of square is 2 cm.

  Perimeter of square = 4× side= 4×2= 8 cm = 0.08 metre.

2. In this case weight of frame is not given. So we can neglect weight of frame.

3. When frame is taken out from liquid , at time only surface tension is act in downward direction by liquid on frame.

4. Now value of surface tension force (F) = surface tension× Length  ...1)

   Where

   surface tension = 2.5 $(\frac{N}{m})$

  Length = perimeter of square = 0.08 (m)

5.  Now from equation 1)

  surface tension force (F) = 2.5×0.08 = 0.2 (N)  

Answer 2

Explanation:

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