Easy MCQ +4 / -1 PYQ · JEE Mains 2021

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 :

  1. A A, B, C, D and E
  2. B A, B and E only Correct answer
  3. C B and D only
  4. D A, C and E only

Solution

(A) True, atom of each element emits characteristic spectrum.<br><br>(B) True, according to Bohr's postulates $mvr = {{nh} \over {2\pi }}$ and hence electron resides into orbits of specific radius called stationary orbits.<br><br>(C) False, density of nucleus is constant.<br><br>(D) False, A free neutron is unstable decays into proton and electron and antineutrino.<br><br>(E) True, unstable nucleus show radioactivity.

About this question

Subject: Physics · Chapter: Atoms and Nuclei · Topic: Bohr's Model of Hydrogen Atom

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