Answer:100 grams of sample of parent isotope will be left after the first half life.
Step-by-step explanation:
Half life of the sample defined as the time taken by the radio active isotope to get reduced to half of its original value present at initial stage.
The initial mass of parent isotope = 200 g
Mass of parent isotope left after the first half life: M
According to definition:
100 grams of sample of parent isotope will be left after the first half life.