Tag: option b: engineering physics

Questions Related to option b: engineering physics

More viscous oil is used in summer than in winter in motors due to

fluid dynamics option b: engineering physics physics

  1. rise in temperature in summer, the viscosity of oil increases.

  2. rise in temperature in summer, the viscosity of oil decreases.

  3. surface tension of oil decreases.

  4. surface tension of oil increases.

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Correct Option: B
Explanation:

Due to rise in temperature viscosity of oil decreases in summers. So more viscous oils are used for better lubricant protection.

With the increasing molecular mass of a liquid, the viscosity .

fluid dynamics option b: engineering physics physics

  1. decreases

  2. increases

  3. no effect

  4. all wrong

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Correct Option: B
Explanation:

With the increasing molecular mass of a liquid, the viscosity increases.
The flow of molecules is inversely proportional to its mass. Hence, liquids with high molecular mass possess greater viscosity.

When cooking oil is heated in a frying pan, the oil moves around in the pan more easily when it is hot. The main reason for this is that with rise in temperature, there is a decrease in

fluid dynamics option b: engineering physics physics

  1. density

  2. surface tension

  3. viscosity

  4. angle of contact

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Correct Option: C
Explanation:

That is true. The temperature dependence of liquid viscosity is the phenomenon by which liquid viscosity tends to decrease (ore, alternatively, its fluidity tends to increase) as its temperature increase.

Viscosity is most closely related to:

viscosity option b: engineering physics properties of matter physics

  1. density

  2. velocity

  3. friction

  4. energy

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Correct Option: C
Explanation:

Viscosity is the property by virtue of which a liquid offers resistance for the relative motion between liquid molecules. Friction is the force which opposes relative motion between any two objects. So, viscosity is most closely related to friction.

Viscosity of the fluids is analogous to:

viscosity option b: engineering physics properties of matter physics

  1. Random motion of the gas molecules

  2. Friction between the solid surfaces

  3. integral motion

  4. Nonuniform motion of solids

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Correct Option: B
Explanation:

Viscosity is the property by virtue of which a liquid offers resistance for the relative motion between its layer.
Friction is the force between two solid surfaces which offers resistance for the relative motion between them. 
So, viscosity of the fluids is analogous to friction between the solid surfaces.

The main cause of viscosity is:

viscosity option b: engineering physics properties of matter physics

  1. force of repulsion between molecules.

  2. cohesive forces.

  3. adhesive forces.

  4. both cohesive and adhesive forces.

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Correct Option: B
Explanation:

When the inter-molecular forces of attraction are strong within a liquid, there is a viscosity. Cohesive forces are attractive forces exist between molecules of the same substance. So, cohesive forces are the main cause of viscosity. Adhesive forces are attractive force between unlike molecules.

The arrow with a pointed tip can move faster in air than that of with a blunt tip.

viscosity option b: engineering physics properties of matter physics

  1. True

  2. False

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Correct Option: A
Explanation:

The arrow with  a pointed tip can move faster in air than that of with a blunt tip because blunt tip arrow has more area of cross section , so it requires more amount of force to create the same amount of pressure as that by the pointed tip .

so given statement is true  , hence option (A) is correct

Viscosity is the property by virtue of which a liquid:

viscosity option b: engineering physics properties of matter physics

  1. occupies minimum surface area.

  2. offers resistance for the relative motion between its layers.

  3. becomes spherical in shape.

  4. tends to gain its deformed position.

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Correct Option: B
Explanation:

Viscosity is the property by virtue of which a liquid offers resistance for the relative motion between it's layer because it's main cause is cohesive force which acts between like molecules and try to bind them. So, it offers resistance for relative motion between liquid molecules.

The cause of viscosity of liquid is:

viscosity option b: engineering physics properties of matter physics

  1. diffusion.

  2. adhesive force.

  3. gravitational force.

  4. cohesive force.

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Correct Option: D
Explanation:

Due to strong cohesive forces between the molecules, any layer in a moving fluid tries to drag the adjacent layer to move with an equal speed and thus produces the effect of viscosity.

Viscosity is exhibited by:

viscosity option b: engineering physics properties of matter physics

  1. Solids, liquids, and gases.

  2. liquids and gases

  3. Solids and gases

  4. Solids and liquids

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Correct Option: B
Explanation:

Viscosity is exhibited by liquids and gases only. In solids, the role of viscosity is played by friction.