Question

Earth's population is about 6.5 billion. Suppose that every person on Earth participates in a process of counting identical particles at the rate of two particles per second. How many years would it take to count 7.30 × 10^23 particles? Assume that there are 365 days in a year.

Answer 1

1 billion=10^9, population=6.5 billion= 6.5*10⁹ peoplem no of particles counted per second per person= 2

6.5*10⁹ billion people can count = 6.5*10⁹*2 particles/second=1.3*10¹⁰ particles/second

1 year =365 days, 1 day=24 hrs, 1hr= 60 min, 1 min= 60sec

1 year= 365*24*60*60 seconds =3.154*10⁷ seconds

hence in 1 year, no of particles can be counted= 3.154*10⁷*1.3*10¹⁰ =4.1*10¹⁷ particles/ year

particles to be counted = 7.3*10²³

hence no of years taken= 7.3*10²³/ (4.1*10¹⁷)=1780488 years