The activity of a radioactive substance is 4700 per minute.

 The activity of a radioactive substance is 4700 per minute. Five minutes later the activity is 2700 per minute. The decay constant is

(a) 0.1108 min-1
(b) 1.1108 min-1
(c) 2.008 -1
(d) 0.0108 min-1

Answer: (a) 0.1108 min-1