Question

A physical quantity is measured and the result is expressed as nu where u is the unit used and n is the numerical value. If the result is expressed in various units then
(a) n ∝ size of u
(b) n ∝ u2
(c) n ∝ √u
(d) n ∝ 1u.

Answer 1

Option (d) n ∝ 1/u.

If the result is expressed in various units then n ∝ 1/u.

Explanation:

Let us take an example of mass,

Suppose if a body has a mass of 10 kg. (In this 10 is the numerical value and kg is the unit).

So if we decrease the size of the unit, Say kg to g then the numerical value will be 10000.  

                                     10 kg = 10000 g.

If the size of the unit Kg will be increased from kg to Quintal then the numerical value will be 0.1.

                                    10 kg = 0.1 Quintal.

From this example, we can say that if the numerical value is decreasing then the unit is increasing and if the unit is decreasing then the numerical value is increasing.

Numerical value can be written as n ∝ 1/u.  

Hence, option (d) is the correct answer.

Answer 2

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Option D is correct