Consider the following statements :
A. Atoms of each element emit characteristics spectrum.
B. According to Bohr's Postulate, an electron in a hydrogen atom, revolves in a certain stationary orbit.
C. The density of nuclear matter depends on the size of the nucleus.
D. A free neutron is stable but a free proton decay is possible.
E. Radioactivity is an indication of the instability of nuclei.
Choose the correct answer from the options given below :
Correct Option: , 2
(A) True, atom of each element emits characteristic spectrum.
(B) True, according to Bohr's postulates
$\mathrm{mvr}=\frac{\mathrm{nh}}{2 \pi}$ and hence electron resides into
orbits of specific radius called stationary orbits.
(C) False, density of nucleus is constant
(D) False, A free neutron is unstable decays into proton and electron and antineutrino.
(E) True unstable nucleus show radioactivity.