NCERT Class 12 Chapter 12 Physics Atoms MCQ

NCERT Class 12 Chapter 12 Physics Atoms MCQ | Questions & Answers: Looking for an article that can help you learn about NCERT Class 12 Chapter 12 Physics Atoms concept? Well, then you have opened the right website. In this article, we have accommodated a series of MCQ questions that enables you to learn Atoms topic quickly.

Page 1 of 3

1. According to classical theory, the path of an electron in Rutherford atomic model is

A. spiral

B. circular

C. parabolic

D. straight line

2. If 13.6 eV energy is required to ionise the hydrogen atom, then energy required to remove an electron from n = 2 is

A. 10.2 eV

B. 0 eV

C. 3.4 eV

D. 6.8 eV.

3. In the Geiger-Marsden scattering experiment, is case of head-on collision the impact parameter should be

A. maximum

B. minimum

C. infinite

D. zero

4. Which of these is true?

A. The alpha particles used in Rutherford's experiment are positively charged particles

B. Dalton assumed that atoms are made up of electrons, protons, and neutrons

C. In Rutherford's alpha scattering experiment, all of the alpha particles passed through the gold foil.

D. JJ Thomson determined the charge and mass of electrons

5. Rutherford’s a-particle experiment showed that the atoms have

A. Proton

B. Nucleus

C. Neutron

D. Electrons

6. In Bohr’s model of an atom which of the following is an integral multiple of h2π?

A. Kinetic energy

B. Radius of an atom

C. Potential energy

D. Angular momentum

7. Isobars have the same:

A. A

B. Z

C. N

D. All the above

8. Which of the following is/are deduced from the Rutherford's scattering experiment?
(1) There are neutrons inside the nucleus.
(2) The sign of the charge of the nuclei is the same as the sign of alpha particles.
(3) Electrons are embedded in the nucleus.

A. (1) only

B. (2) only

C. only

D. (1) (2) and (3)

9. Rutherford’s atomic model was unstable because

A. nuclei will break down

B. electrons do not remain in orbit

C. orbiting electrons radiate energy

D. electrons are repelled by the nucleus

10. In Bohr’s model, the atomic radius of the first orbit is rQ. Then, the radius of the third orbit is

A. r₀/9

B. r₀

C. 9r₀

D. 3r₀

Page 2 of 3

11. The ratio of kinetic energy to the total energy of an electron in a Bohr orbit of the hydrogen atom is

A. 1 : 1

B. 1 : -1

C. 2 : -1

D. 1 : -2

12. In scattering, the impact parameter b is defined as the:

A. maximum kinetic energy of the scattering projectile

B. distance of closest approach between projectile and target

C. closest distance between projectile and target if there were no deflection

D. distance between projectile and target for which there is maximal deflection

13. According to Bohr’s model of hydrogen atom

A. the linear velocity of the electron is quantised

B. the angular velocity of the electron is quantised

C. the linear momentum of the electron is quantised

D. the angular momentum of the electron is quantised

14. The K.E. of the electron in an orbit of radius r in hydrogen atom is proportional to CBSE Class12 Physics Atoms (14Q)

A. (a)

B. (b)

C. (c)

D. (d)

15. According to the Rutherford’s atomic model, the electrons inside the atom are

A. stationary

B. not stationary

C. centralized

D. None of these

16. The alpha particle scattering experiment was carried out by:

A. J. Chadwick

B. Rutherford

C. Goldstein

D. J.J. Thomson

17. As the quantum number increases, the difference of energy between consecutive energy levels

A. remain the same

B. increases

C. decreases

D. sometimes increases and sometimes decreases.

18. The ratio between Bohr radii is

A. 1 : 2 : 3

B. 2 : 4 : 6

C. 1 : 4 : 9

D. 1 : 3 : 5

19. What is the valence electron in alkali metal?

A. f-electron

B. p-electron

C. s-electron

D. d-electron

20. We know that the Rutherford model of the atom is superior to the Thompson model because when alpha particles are scattered from atoms:

A. the deflected angle is always large

B. they are usually observed with kinetic energy between 5 and 10 MeV

C. some alpha particles are deflected to large angles

D. the deflected angle is usually small

Page 3 of 3

21. When hydrogen atom is in its first excited level, it’s radius is

A. four times, it ground state radius

B. twice times, it ground state radius

C. same times, it ground state radius

D. half times, it ground state radius.

22. The longest wavelength in Balmer series of hydrogen spectrum will be

A. 6557 Å

B. 1216 Å

C. 4800 Å

D. 5600 Å

23. As the quantum number increases, the difference of energy between consecutive energy levels

A. remain the same

B. increases

C. decreases

D. sometimes increases and sometimes decreases.

24. Which of the following series in the spectrum of hydrogen atom lies in the visible region of the electromagnetic spectrum?

A. Paschen series

B. Balmer series

C. Lyman series

D. Brackett series

25. In terms of Rydberg constant R, the wave number of the first Balmer line is

A. R

B. 3R

C. 5R36

D. 8R9