Question

A radioactive isotope has a halflife of 20 days is 100 gm of the substance is taken the weight of the isotope
remaining after 40 days is
Option 1:
25 gms
w
Option 2:
2.5 gms
Option 3:
60 gms
Option 4:
40 gms​

Answer 1

Answer:

option 1. 25 gms

Explanation:

intial mass = 100 gms

half life = 20 days

its means after 20 days its mass becomes half of its initial mass.

for time 40 days (i.e. after 2 half life) its mass becomes 1/4th of its initial