PrepBharat

1. The value of surface tension of a liquid at critical temperature is
a) Zero
b) Infinite
c) Between 0 and \[\infty\]
d) Can not be determined

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2. The spherical shape of rain-drop is due to
a) Density of the liquid
b) Surface tension
c) Atmospheric pressure
d) Gravity

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3. Surface tension is due to
a) Frictional forces between molecules
b) Cohesive forces between molecules
c) Adhesive forces between molecules
d) Gravitational forces

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4. When there is no external force, the shape of a liquid drop is determined by
a) Surface tension of the liquid
b) Density of liquid
c) Viscosity of liquid
d) Temperature of air only

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5. Soap helps in cleaning clothes, because
a) Chemicals of soap change
b) It increases the surface tension of the solution
c) It absorbs the dirt
d) It lowers the surface tension of the solution

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6. A pin or a needle floats on the surface of water, the reason for this is
a) Surface tension
b) Less weight
c) Upthrust of liquid
d) None of the above

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7. Coatings used on raincoat are waterproof because
a) Water is absorbed by the coating
b) Cohesive force becomes greater
c) Water is not scattered away by the coating
d) Angle of contact decreases

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8. If temperature increases, the surface tension of a liquid
a) Increases
b) Decreases
c) Remains the same
d) Increases then decreases

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9. A drop of oil is placed on the surface of water. Which of the following statement is correct
a) It will remain on it as a sphere
b) It will spread as a thin layer
c) It will be partly as spherical droplets and partly as thin film
d) It will float as a distorted drop on the water surface

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10.The temperature at which the surface tension of water is zero
a) 0°C
b) 370°C
c) Slightly less than 647 K
d) Both b and c

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