Question

A sample of rock is found to contain 200 grams of a parent isotope.how many grams of the parent isotope will remain after one half life

Answer 1

50

Step-by-step explanation:

Answer 2

Answer: 100 grams of the parent isotope will remain after one half life.

Step-by-step explanation:

Mass of the isotope present at initial stage =
`N_o=200 g`

The mass of the parent isotope left after the time ,t=N

Time taken by the samle ,t =
`t_{(1)/(2)}`

The half life of the sample :
`t_{(1)/(2)}`

`N=N_o* e^(-\lambda t)`

`\lambda =\frac{0.693}{t_{(1)/(2)}}`

`\ln[N]=ln[N^o]-\frac{0.693}{t_{(1)/(2)}}* t_{(1)/(2)}`

`2=([N_o])/([N])`

`[N]=(N_o)/(2)=(200 g)/(2)=100 g`

100 grams of the parent isotope will remain after one half life.