Moderate

A soap bubble assumes a spherical surface. Which of the following statement is wrong

Correct answer: C. The pressure of air inside the bubble is less than the atmospheric pressure; that is why the atmospheric pressure has compressed it equally from all sides to give it a spherical shape

  • A. The soap film consists of two surface layers of molecules back to back
  • B. The bubble encloses air inside it
  • C. The pressure of air inside the bubble is less than the atmospheric pressure; that is why the atmospheric pressure has compressed it equally from all sides to give it a spherical shape
  • D. Because of the elastic property of the film, it will tend to shrink to as small a surface area as possible for the volume it has enclosed

Explanation

The correct answer is Option C. In a soap bubble, the pressure inside the bubble is higher than the atmospheric pressure due to the surface tension of the soap film. This surface tension attempts to reduce the surface area of the bubble, leading to an increase in internal pressure to balance it out. The incorrect statement is that the pressure inside is less than atmospheric pressure; instead, it is greater. Option A is correct as the soap film is made of two molecular layers. Option B is correct because a bubble indeed encloses air. Option D is also true, as the bubble minimizes surface area due to its elastic property.

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