Question

One second is required to count two wheat grain, then calculate the time (in years) required to count one mole of wheat grains.

Answer 1

1 sec is required to count 2 wheat grain.

It means to count one mole of wheat grain the time required will be :–
2grain = 1sec
1grain = 1/2sec
6.022×10^23grain=1/2×6.022×10^23sec
6.022×10^23grain=3.011×10^23sec

we know that,
60×60×24×365sec=1years
31536000sec = 1years
1sec = 1/31536000year
3.011×10^23sec=1/31536000×3.011×10^23years
3.011×10^23sec=9.49×10^16years(approx).