Chapter 2, Problem 124A

Interpretation Introduction

Interpretation:

The reason for not choosing the alternative standards should be determined.

Concept introduction:

SI units are international system of units that helps us in measuring the different aspects. The SIsystem helps to standardize the measurement system throughout the globe.

Answer to Problem 124A

Other methods of weight measurement are not reliable and practical for using in day to day life.

Explanation of Solution

The modern standard of kilogram is the weight of platinum-iridium cylinder in vacuum, but in practical environment it is slightly changed due to the temperature, humidity and presence of unwanted matter.

So, in 2007, scientist proposed calculation of mass on the basis of Avogadro’s number, but this concept was not accepted, as the calculation of mass using Avogadro’s number was practically not applicable.

In 2018, the calculation was done using Plank’s constant, which is measured in Joules per second or kg m² per second. So, here also, the basic unit used for measurement was kilogram, which made scientist to stuck on the kilogram standard.