Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • NCERT
  • A great physicist of this century (P.A.M. Dirac) loved playing with numerical values of Fundamental constants of nature. This led him to an interesting observation.

Q 2.33: A great physicist of this century (P.A.M. Dirac) loved playing with numerical values of fundamental constants of nature. This led him to an interesting observation. Dirac found that from the basic constants of atomic physics (c, e, mass of electron, mass of proton) and the gravitational constant G, he could arrive at a number with the dimension of time. Further, it was a very large number, its magnitude being close to the present estimate on the age of the universe (~15 billion years). From the table of fundamental constants in this book, try to see if you too can construct this number (or any other interesting number you can think of ). If its coincidence with the age of the universe were significant, what would this imply for the constancy of fundamental constants?

Answers (1)

best_answer

T = \frac{e^4}{16\ \pi^2 \ \epsilon _{0}^{2}\ m_{p} m_{e}^2\ c^3\ G } \ s

The above equation consisting of basic constants of atomic physics and the gravitational constant G has the dimension of time.

e = charge of Electron = -1.6\times10^{-19} C

\epsilon _{0} = absolute permittivity = 8.85\times10^{-12} F/m

m_{p} = Mass of the Proton = 1.67\times10^{-27} kg

m_{e} = Mass of the Electron = 9.1\times10^{-31} kg
c = Speed of light in vacuum = 3\times10^8 m/s
G = Universal Gravitational constant = 6.67\times10^{11} Nm^2kg^{-2}

Considering T as the age of the universe and putting the values of the constants, we get:

\therefore T \approx 6\times10^9\ years

The age of the universe  ≈ 6 billion years.!

 

Posted by

Devendra Khairwa

View full answer

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support
cuet_ads

Similar Questions

Trending Articles/News

anam-khan

CBSE Date Sheet 2025 (Out) Live: Class 10, 12 board exam time table at cbse.gov.in; syllabus, sample papers
anam-khan

CBSE Class 12 board exam date sheet 2025 out; exams from February 15 to April 4
anam-khan

When will CBSE Board exam 2025 date sheet be released for Class 10, 12?

Latest Question