Viscosity of a Liquid (Stoke's Law)

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Questions and Answers

What primary factor affects the viscosity of a liquid at different temperatures?

Molecular Weight

Density

Chemical Reactivity

Molecular Structure (correct)

Which intermolecular force primarily influences the viscosity of a liquid?

Van der Waals Forces (correct)

Nuclear Force

Gravitational Force

Electromagnetic Force

How do impurities in a liquid generally affect its viscosity?

Lower the density

Have no effect on viscosity

Increase the boiling point

Alter the intermolecular forces (correct)

Which of the following factors has the least impact on the viscosity of a liquid?

Color of the liquid Signup and view all the answers

What is the effect of increasing pressure on the viscosity of a liquid?

Increases viscosity moderately Signup and view all the answers

Which tool is used in the experience to examine samples under magnification?

Glass slide Signup and view all the answers

What is surface tension best described as?

The effect that makes the surface layer of a liquid behave like an elastic sheet Signup and view all the answers

Which of the following materials was mentioned as part of the experience tools?

Paraffin wax Signup and view all the answers

Which characteristic of liquids is demonstrated by surface tension?

Cohesion Signup and view all the answers

In the context of the experience, what could the different colors of paraffin represent?

Different sample specimens Signup and view all the answers

What is the calculated slope from the given data?

500 cm/s² Signup and view all the answers

What is the value of 'g' calculated from the slope?

10 m/s² Signup and view all the answers

Which value corresponds to the time (t) when the distance is 80 cm?

0.38 sec Signup and view all the answers

What is the change in time (∆t) between the distances of 90 cm and 80 cm?

0.02 sec Signup and view all the answers

How does the acceleration due to gravity (g) relate to the slope value?

g equals twice the slope Signup and view all the answers

What is the calculated value of $X$ in the angle of contact calculation?

0.4 Signup and view all the answers

What is the value of $Y$ in the angle of contact calculation?

0.3 Signup and view all the answers

What is the final calculated angle $ heta$ in the angle of contact calculation?

36.86 Signup and view all the answers

In the context of free fall, what is the primary aim of the experiment mentioned?

To determine the ground acceleration (g) Signup and view all the answers

Which of the following equations is used to find $tan \theta$ in the calculation?

$tan \theta = \frac{X}{Y}$ Signup and view all the answers

What happens to the surface tension coefficient of a liquid when its temperature is raised?

It decreases Signup and view all the answers

Which of the following factors does not affect the surface tension coefficient of a liquid?

Color of the Liquid Signup and view all the answers

Which of these is NOT a factor that affects surface tension of a liquid?

The shape of the container Signup and view all the answers

How do surfactants, such as soap, generally affect the surface tension of a liquid?

They lower surface tension Signup and view all the answers

If a liquid has impurities, how does it generally affect the surface tension coefficient?

It decreases Signup and view all the answers

What is the formula used to calculate Young's modulus from the slope?

Y = slope × W Signup and view all the answers

Which factors do NOT affect Young's modulus?

Strain Rate Signup and view all the answers

What will be the slope calculation using the given values for mass 50 gm and mass 40 gm?

10 Signup and view all the answers

What does Young's modulus depend on?

Material composition, temperature, microstructure, impurities, and defects Signup and view all the answers

What is the value of Young's modulus for the material given that the slope calculation resulted in 0.005 and assuming W is 980 g?

4.9 Signup and view all the answers

Study Notes

Viscosity of a Liquid (Stock's Method)

Aim: To determine the viscosity of a liquid (glycerin) using Stoke's Law.
Tools:
- One-ended closed glass tube filled with glycerin
- Metal balls of various sizes
- Metric ruler
- Stopwatch
- Micrometer/ruler
Purpose of dropping balls from one position: To reduce experimental errors and ensure consistent results.
Factors affecting viscosity: Temperature, molecular structure, intermolecular forces, pressure, impurities.
Calculation of viscosity:
- Data collected includes: ball diameter (D), radius (r), radius squared (r²), time taken for fall (t), velocity (v).
- Formula used in calculation: n = 5 * g * (p_s - p_l) * slope (where 'n' is viscosity; g = gravity, p_s=density of sphere, p_l = density of liquid, and the slope is derived from a graph of velocity vs radius squared).

Boyle's Law

Aim: To determine atmospheric pressure using Boyle's Law.
Tools:
- Boyle's device (a U-shaped glass tube with one end closed)
- Mercury
- Thermometer
Why mercury: Mercury's high density, non-compressibility, and stability make it suitable for precise measurements.
Relationship between pressure and volume: Inversely proportional (P1V1 = P2V2)
Convex surface of mercury in tube: Cohesive forces between mercury molecules are stronger than adhesive forces between mercury and glass.
Calculation of atmospheric pressure: Data collected includes: initial volume, final volume, and corresponding pressure readings. The formula used for calculating atmospheric pressure is P_ο= |-76|.

Young's Modulus of Elasticity

Aim: To determine the Young's modulus of a material.
Tools:
- Horizontal ruler
- Holder
- Weights
- Micrometer
Factors affecting Young's modulus: Material composition, temperature, microstructure, impurities, defects.
Stress: Force acting on a unit area.
Compliance: The ability of a material to deform or respond to an applied stress.
Calculation of Young's Coefficient: Data collected includes: mass (M) and change in length (AL). Formula is Y = slope × W * 980, where slope is calculated by dividing change in AL (in cm) by mass change (in gm) and W is the width used.

Surface Tension

Aim: To study surface tension and its relation to wax color.
Tools:
- Paraffin wax in different colors
- Glass slide
- Microscope
Surface tension: The phenomenon where the surface layer of a liquid acts like an elastic sheet, enabling certain objects to float.
Factors affecting surface tension: Temperature, nature of the liquid, impurities, surfactants.
Cohesive forces: Attractive forces between molecules within a substance.
Adhesive forces: Attractive forces between molecules of different substances, as seen when a liquid affects a material.
What happens to surface tension at boiling point: Becomes zero.
What happens to the coefficient of surface tension when heated: Decreases.

Free Fall

Aim: To determine the acceleration due to gravity (g).
Tools:
- Metal ball attached to a magnetic device
- Mechanical shock sensitive switch
- Electronic watch
- Metric ruler
Method: Dropping the metal ball and timing its fall from varying points.
Calculation of acceleration: Data collected includes distance (S), time (t), squared time (t²), and the slope which is calculated from graph of S against t². Formula is g = 2 × slope.

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Description

Explore the principles of viscosity through Stoke's Law in this quiz. You will learn to calculate the viscosity of glycerin using various experimental tools and understand the factors that influence viscosity. Test your knowledge on the methodology and calculations involved in this practical experiment.