MCQ Detailed View

A Lactometer is a simple scientific instrument used to measure the specific gravity (relative density) of milk. It is a special type of hydrometer, an instrument that determines how dense a liquid is compared to water. The specific gravity of milk provides information about its purity and quality, as any addition of water or removal of cream affects its density.✅ Working Principle:

The lactometer consists of:

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  A long glass stem with a scale marked in degrees.

  
  


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  A weighted bulb at the bottom, allowing it to float upright in the milk sample.

  
  

When placed in pure milk:

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  Milk has a slightly higher density than water due to dissolved nutrients such as fat, lactose, proteins, and minerals.

  
  


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  The lactometer floats at a specific level, typically indicating a specific gravity between 1.026 and 1.033.

  
  

If water is added to milk:

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  Its density decreases.

  
  


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  The lactometer sinks deeper, showing a lower reading.
  This helps detect milk adulteration easily.

  
  

✅ Importance:

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  Widely used in dairy farms, milk collection centers, and quality testing laboratories.

  
  


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  Provides a quick, cost-effective method to check milk quality without needing complex equipment.

  
  


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  Ensures fair trade practices by preventing dilution or manipulation of milk before sale.

  
  

❌ Other Options Explained:

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  Honey: Much denser than water, requiring different hydrometers.

  
  


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  Water: Standard reference liquid with fixed density (1.000).

  
  


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  Olive oil: Lighter than water and tested with oil-specific devices.

  
  

✅ Final Answer:

A Lactometer is used to measure the specific gravity of milk, making it a key instrument in everyday science for monitoring food quality and purity