1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

# The mean lives of a radioactive material for α and β radiations are 1620 years and 520 years respectively. The material decays simultaneously for α and β radiations.The time after which one fourth of the material remains undecayed is

A
546 years
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
324 years
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
720 years
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
840 years
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

## The correct option is A 546 yearsLet, the mean life of a radioactive material for α radiations is τα=1620years,and the mean life of a radioactive material for β radiations is τβ=520years,NN0=14 ..........(given)The mean life of a radioactive material for both radiations will be:τ=τα.τβτα+τβτ=1620×5201620+520τ=393.64≈394yearsThe time of decay of a radioactive material is:T=τ2.303log10N0NT=394×2.303log10(4)T=394×2.303×0.602T=546.243≈546years

Suggest Corrections
0
Join BYJU'S Learning Program
Related Videos
Rutherfords Setup and Predictions
PHYSICS
Watch in App
Join BYJU'S Learning Program