MCQ Detailed View

The dyne is a unit of force in the centimeter-gram-second (CGS) system of units. It is not commonly used today because the SI (International System of Units) has largely replaced CGS, but it is still important in understanding classical physics and older scientific literature.

Definition of Dyne

1 dyne is defined as the force required to accelerate a mass of 1 gram by 1 centimeter per second squared (cm/s²).

1 dyne=1 g⋅cm/s21 \, dyne = 1 \, g \cdot cm/s^21dyne=1g⋅cm/s2

Conversion to Newton

The SI unit of force is the Newton (N). Since 1 Newton is the force required to accelerate 1 kilogram by 1 m/s², the relation between Newton and dyne is:

1 N=105 dyne1 \, N = 10^5 \, dyne1N=105dyne

So, 1 dyne is a very small unit of force compared to a Newton.

Why Dyne Belongs to Force (Correct Option B)

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  Quantity (Option A): Not a measurable physical unit.

  
  


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  Pressure (Option C): The CGS unit of pressure is barye (dyne/cm²), not dyne itself.

  
  


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  Depth (Option D): Measured in units of length (cm, m, ft, etc.), not dyne.

  
  

Therefore, the correct choice is Force.

Applications of Dyne

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  In surface tension studies, force is often expressed in dyne per centimeter (dyne/cm).

  
  


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  In older mechanics and fluid dynamics books, dyne is commonly used.

  
  


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  Dyne-based units helped establish foundations for modern SI system.

  
  

Key Facts

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  Dyne is part of the CGS system, which uses centimeter, gram, and second.

  
  


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  Rarely used in modern physics, but still appears in textbooks and research papers.

  
  


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  Provides insight into the historical development of measurement systems.