For a radioactive sample with decay constant

PHYSICS · Single correct · A Level · Physics · Nuclear physics · Nuclear physics

Problem

\lambda

, which expression gives the time

t

required for the sample to decay to a fraction

f

of its initial activity? (a)

t = \dfrac{\ln 2}{\lambda}\,\ln\!\left(\dfrac{1}{f}\right)

(b)

t = \dfrac{1}{\lambda}\,(1-f)

(c)

t = \dfrac{1}{\lambda}\,\ln\!\left(\dfrac{1}{f}\right)

(d)

t = \dfrac{1}{\lambda}\,\ln f