Properties of Solids & Liquids-Surface Energy and Surface Tension (KVPY Stream SB-SX (Class 12 & 1st Year BSC) Physics): Questions 1 - 2 of 2

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Question number: 1

» Properties of Solids & Liquids » Surface Energy and Surface Tension

Appeared in Year: 2013

MCQ▾

Question

Young-Laplace law states that the excess pressure inside a soap bubble of radius R is given by P=4σR where σ is the coefficient of surface tension of the soap. The Eӧtvӧs number E0 is a dimensionless number that is used to describe the shape of bubbles rising through a surrounding fluid. It is a combination of g (the acceleration due to gravity), ρ (the density of the surrounding fluid), σ and a characteristic length scale L which could be the radius of the bubble. A possible expression for E0 is –

Choices

Choice (4) Response

a.

ρgσL3

b.

ρL2σg

c.

ρgL2σ

d.

gL2σρ

Question number: 2

» Properties of Solids & Liquids » Surface Energy and Surface Tension

MCQ▾

Question

A hollow sphere has a small hole in it. On lowering the sphere in a tank of water, it is observed that water enters into the hollow sphere at a depth of 60 cm below the surface. Surface tension of water is 7×102Nm1 . The diameter of the hole is,

Choices

Choice (4) Response

a.

121mm

b.

128mm

c.

114mm

d.

142mm

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