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प्रश्न
Why do we have different units for the same physical quantity?
उत्तर
The value of any given physical quantity may vary over a wide range, therefore, different uns of the same physical quantity are required. e.g., The length of a pen can be easily measured in cm, the height of a tree can be measured in metres, the distance between two cities can be measured in kilometres and the distance between two heavenly bodies can be measured in light years.
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