In C.G.S unit, dynamic viscosity is expressed as:
- A.Poise
- B.Pa-s
- C.Stoke
- D.None of the above
Correct answer
Explanation
The correct answer is A, Poise. Dynamic viscosity measures how strongly a fluid resists flowing, and in the centimetre gram second system it is measured in poise, a unit named after the French physician Jean Louis Marie Poiseuille, who studied the flow of blood in narrow tubes. One poise is one dyne second per square centimetre, and since the SI unit is the pascal second, one pascal second equals ten poise. Thin liquids are usually quoted in centipoise: water at room temperature is about one centipoise while honey runs into thousands. Option B is wrong because the pascal second is the SI unit of dynamic viscosity, and the question asks for the CGS unit. Option C is wrong because the stoke is the CGS unit of kinematic viscosity, which is dynamic viscosity divided by density. Option D is wrong because option A already names the right unit. Exam tip: dynamic viscosity in poise and pascal second, kinematic viscosity in stoke and square metre per second.
Practice Questions
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- A.Galileo
- B.Martin Luther
- C.Johannes Kepler
- D.Copernicus
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In 1609 Kepler showed that the planets move around the Sun in elliptical orbits, with the Sun at one focus of the ellipse.
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- B.Urea is produced in blood.
- C.Urea is produced from digestion of starch.
- D.Urea is produced in lung and kidney.
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- A.Condenser-Objective lens-Eyepiece-Body tube
- B.Objective lens-Condenser-Body tube-Eyepiece
- C.Condenser-Objective lens-Body tube-Eyepiece
- D.Eyepiece-Objective lens-Body tube-Mirror
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Read the full explanation →Which one of the following statements regarding haemoglobin is correct?
- A.Haemoglobin present in RBC can carry only oxygen but not carbon dioxide.
- B.Haemoglobin of RBC can carry both oxygen and carbon dioxide.
- C.Haemoglobin of RBC can carry only carbon dioxide.
- D.Haemoglobin is only used for blood clotting and not for carrying gases.
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- B.Histones are proteins that are present in nucleus in association with DNA.
- C.Histones are proteins associated with lipids in the cytosol.
- D.Histones are proteins associated with carbohydrates in the cytosol.
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