1 The activity of a substance changes from 700 s1 to 500 s1 in 30 minutes. Find its half-life in minutes
Answer (1)
22nd Mar, 2020
Hi,
From equation of radioactivity we know
At=A0et
[WhereAt=Amount of material at time 't', A0=Amount of substance att=0, =decay constant, t=time.]
Taking log we have
ln[AtA0]=t
For half lifeAt=2A0.
ln2=t1/2__(A) [t1/2=half life]
From given condition.
ln[500700]=(30min)__(B)
(A)-(B)
ln[7/5]ln2=30t1/2
t1/2=ln[7/5]ln230t1/2=0.3360.69330
t1/2=61.8min
From equation of radioactivity we know
At=A0et
[WhereAt=Amount of material at time 't', A0=Amount of substance att=0, =decay constant, t=time.]
Taking log we have
ln[AtA0]=t
For half lifeAt=2A0.
ln2=t1/2__(A) [t1/2=half life]
From given condition.
ln[500700]=(30min)__(B)
(A)-(B)
ln[7/5]ln2=30t1/2
t1/2=ln[7/5]ln230t1/2=0.3360.69330
t1/2=61.8min
Comments (0)
