Mastering The International System Of Units And Its Fundamental Constants

The video explains the International System of Units (SI), its history, and the transition from definitions based on daily phenomena to those based on physical constants. It highlights the 2019 revision, which assigns exact values to fundamental constants like Planck's constant and Avogadro's number, ensuring consistent and precise measurements worldwide.

Which year was the International System of Units (SI) officially published?

• 2019

• 1960

• 1945

• 1875

Which of the following countries has not adopted the SI system?

• Canada

• United States of America

• Australia

• United Kingdom

What was the original basis for defining units like the meter and second?

• Astronomical observations

• Physical constants

• Daily life phenomena

• Mathematical calculations

As of May 2019, what is the exact value of Planck's constant?

• 1.602176634 x 10^-19

• 6.62607015 x 10^-34

• 1.380649 x 10^-23

• 6.02214076 x 10^23

Which constant is defined as exactly 1.602176634 x 10^-19 coulombs?

• Planck's constant

• Boltzmann's constant

• Avogadro's constant

• Elementary charge

What is the exact speed of light in meters per second?

• 683,000,000

• 540,000,000

• 919,263,177

• 299,792,458

The luminous efficacy of monochromatic radiation at 540 terahertz is exactly how many lumens per watt?

• 299,792,458

• 919,263,177

• 683

• 540

Which constant is used to define the mole in the SI system?

• Elementary charge

• Boltzmann's constant

• Avogadro's constant

• Planck's constant

How is the kelvin defined in the SI system?

• Using the speed of light

• Using the Avogadro number

• Using the Boltzmann constant

• Using the elementary charge

Which base unit is defined using the transition frequency of cesium-133?

• Meter

• Second

• Kilogram

• Candela