A radioactive sample disintegrates by 10% during one month. How much fraction will disintegrate in four months:

According to question, 10% of a radioactive samples disintegrates in one month.Fraction of radioactive sample remain undecayed after one month, 0.9.Let N0 is initial number of samples.Fraction of radioactive sample remain undecayed after four months is given as NN0=(0.9)4=0.6561.Fraction of sample decayed after four months=1−0.6561=0.3439 or 34.69%.