Question

Which of the following is/are incorrect ?

• A. 1 curie $=3.7\times {10}^{10}$dis
• B. Actinium series starts with $U^{238}$
• C. Nuclear isomers contain the same number of protons and neutrons.
• D. The decay constant is independent of the amount of the substance taken

Answer 1

Answer: (C), (D)

The correct options are
C The decay constant is independent of the amount of the substance taken
D Nuclear isomers contain the same number of protons and neutrons.

Nuclear isomers have same atomic number and atomic mass number. So, nuclear isomers contain the same number of protons and neutrons.
The decay constant depends upon initial amount of substance, $K=\frac{2.303}{t}log\frac{a}{a-x}$ so the decay constant is independent of the amount of the substance taken.
Hence, options C & D are correct.