PrepBharat

1. A mercury drop does not spread on a glass platebecause the angle of contact between glass and mercury is
a) Acute
b) Obtuse
c) Zero
d) \[90^{\circ}\]

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2. A liquid is coming out from a vertical tube. The relation between the weight of the drop W, surface tension of the liquid T and radius of the tube r is given by, if the angle of contact is zero
a) \[W=\pi r^{2}T\]
b) \[W= 2\pi rT\]
c) \[W= 2r^{2}\pi T\]
d) \[W=\frac{3}{4}\pi r^{3}T\]

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3. The parts of motor cars are polished by chromium because the angle of contact between water and chromium is
a) \[0^{\circ}\]
b) \[90^{\circ}\]
c) Less than \[90^{\circ}\]
d) Greater than \[90^{\circ}\]

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4. A glass plate is partly dipped vertically in the mercury and the angle of contact is measured. If the plate is inclined, then the angle of contact will
a) Increase
b) Remain unchanged
c) Increase or decrease
d) Decrease

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5. The liquid meniscus in capillary tube will be convex, if the angle of contact is
a) Greater than 90°
b) Less than 90°
c) Equal to 90°
d) Equal to 0°

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6. The value of contact angle for kerosene with solid surface.
a) 0°
b) 90°
c) 45°
d) 33°

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7. Nature of meniscus for liquid of 0^o angle of contact
a) Plane
b) Parabolic
c) Semi-spherical
d) Cylindrical

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8. A liquid wets a solid completely. The meniscus of the liquid in a sufficiently long tube is
a) Flat
b) Concave
c) Convex
d) Cylindrical

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9. What is the shape when a non-wetting liquid is placed in a capillary tube
a) Concave upward
b) Convex upward
c) Concave downward
d) Convex downward

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10. For which of the two pairs, the angle of contact is same
a) Water and glass; glass and mercury
b) Pure water and glass; glass and alcohol
c) Silver and water; mercury and glass
d) Silver and chromium; water and chromium

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