# NEET Physics Nuclei Questions Solved

BOARD

(a) State the law of radioactive decay. Write the SI unit of 'activity'.

(b) There are  radioactive nuclei in a given radioactive sample. If the half life of the sample is 20 s, how many nuclei will decay in 10 s?

3 marks

(a) Statement : Rate of decay of a given radioactive sample is directly propotional to the total number of undecayed nuclei present in the sample.                              (1)mark

[Alternatively: $\frac{dN}{dt}\propto N$]

Unit- becquerel(Bq)                                                                           (1/2)mark

(b)

Difficulty Level: