Question

Which property of milk can be determined with Stalagmometer ?

• A. Viscosity
• B. Dialectric Constant
• C. Surface Tension
• D. Specific conductance

Hint:

Associate "Stalagmometer" with "Surface Tension" (both starting with 'S'). This simple alphabetical pairing helps avoid confusion with viscosity.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
A stalagmometer is a laboratory instrument used to measure the surface tension of liquids by assessing the mass or number of drops released from a vertical capillary tube.

Step 2: Detailed Explanation:
- The stalagmometer operates on the drop-weight or drop-number method.
- Surface tension is directly proportional to the weight of a single droplet that falls from the capillary tip:
\[ m \cdot g = 2 \pi \cdot r \cdot \gamma \]
where \(\gamma\) is the surface tension, \(m\) is the drop mass, and \(r\) is the tube radius.
- By comparing the number of drops formed by a given volume of milk with that of a reference liquid (like pure water), the surface tension of milk can be calculated.
- Viscosity is measured using a viscometer (such as an Ostwald viscometer).
- Specific conductance is measured with a conductivity meter.

Step 3: Final Answer
The surface tension of milk is determined using a stalagmometer.