00:01
Hello students, here the decay rate or activity is defined as lambda into n.
00:07
Now at t equals to zero, activity a zero is given by 548 second inverse.
00:22
Now at t equals to 48 minute, a equals to lambda into n, where n is the element left at t equals to 48 minute equals to 213 second inverse.
00:46
Now dividing this two, we can write n by n zero equals to 213 divided by 548.
00:55
Now we know that from radioactive decay law n by n zero equals to the power minus lambda.
01:02
So that is lambda t equals to the power minus lambda t equals to 213 by 548.
01:10
So from this we can write lambda t equals to ln or lambda equals to 1 by t ln 548 divided by 213.
01:30
So lambda equals to 1 by 48 minute, here time is 48 minute ln 548 by 213 minute inverse.
01:47
So lambda equals to 0 .0196 minute inverse.
01:55
Now we know that lambda equals to 0 .693 by half life t half...