Tag: fluid dynamics

Questions Related to fluid dynamics

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.