The disintegration rate of a radioactive sample at a certain instant is 4750 dpm . Five minute later rate becomes 2700 disintegration per minute . Then the decay constant is

Question

$(a)\;0.26 per \;min\qquad(b)\;0.113 per\; min\qquad(c)\;0.35 per\; min\qquad(d)\;0.05 per\; min$