Unit change and numerical value – Rankers Physics

Dimensions: Practice Problem & Solution

Assertion (A): When we change the unit of measurement of a quantity, its numerical value changes. Reason (R): Smaller the unit of measurement smaller is its numerical value.  
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Dimensions. Understanding the underlying formula is key to arriving at the correct answer below:

The physical magnitude is invariant, expressed as \(n u = \text{constant}\). Therefore, numerical value is inversely proportional to the unit size. A smaller unit leads to a larger numerical value, making R false.

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