Class 12 Physics MCQ Chapter 12 Atoms English Medium
Sharpen your understanding of atomic physics with our Class 12 Physics MCQ Chapter 12 Atoms English Medium study material. This article provides a comprehensive collection of important multiple-choice questions (MCQs) with answers, specially designed for AHSEC Higher Secondary students aiming for excellent performance in Physics examinations.
The chapter Atoms focuses on the structure of atoms and the development of atomic models that revolutionized modern science. Students will explore topics such as Thomson’s atomic model, Rutherford’s alpha-particle scattering experiment, Bohr’s atomic model, energy levels, hydrogen spectrum, and the emission and absorption of radiation. These concepts are fundamental to understanding the behavior of atoms and frequently appear in board examination question papers.
Prepared according to the latest AHSEC syllabus and examination pattern, these MCQs help students strengthen conceptual knowledge, improve analytical thinking, and become familiar with important objective questions. Regular practice is an effective way to boost confidence and improve accuracy before examinations.
Whether you are revising the chapter for a class test or preparing for the AHSEC Higher Secondary Final Examination, these Chapter 12 MCQ solutions will provide valuable support for effective learning and exam success.
PART II
Class 12 Physics MCQ Chapter 12 Atoms
VSA & MCQ
I. Very Short Answer Questions
Q. What is an atom?
Ans: The smallest unit of an element that retains its properties.
Q. Who proposed the nuclear model of atom?
Ans: Ernest Rutherford.
Q. What was Rutherford’s experiment?
Ans: Alpha particle scattering experiment.
Q. What is Rutherford’s model?
Ans: Atom has a small dense positively charged nucleus with electrons revolving around it.
Q. What was the limitation of Rutherford model?
Ans: It could not explain stability of atom.
Q. Who proposed Bohr’s model?
Ans: Niels Bohr.
Q. What is Bohr’s first postulate?
Ans: Electrons revolve in stable orbits without radiating energy.
Q. What is Bohr’s second postulate?
Ans: Angular momentum is quantized, mvr = nh/2π.
Q. What is Bohr’s third postulate?
Ans: Radiation is emitted or absorbed during transition.
Q. What is energy of nth orbit?
Ans: E_n = −13.6 / n² eV.
Q. What is radius of nth orbit?
Ans: r_n = n²a₀.
Q. What is ground state?
Ans: Lowest energy state.
Q. What is excited state?
Ans: Higher energy state.
Q. What is ionization energy?
Ans: Energy required to remove electron from ground state.
Q. What is hydrogen spectrum?
Ans: Line spectrum emitted by hydrogen atom.
Q. What is Lyman series?
Ans: Transitions ending at n = 1.
Q. What is Balmer series?
Ans: Transitions ending at n = 2.
Q. What is Paschen series?
Ans: Transitions ending at n = 3.
Q. What is Rydberg formula?
Ans: 1/λ = R(1/n₁² − 1/n₂²).
Q. What is Rydberg constant?
Ans: R ≈ 1.097 × 10⁷ m⁻¹.
Q. What is spectral line?
Ans: Specific wavelength emitted.
Q. What is quantization?
Ans: Physical quantity takes discrete values.
Q. What is angular momentum quantization?
Ans: mvr = nh/2π.
Q. What is energy transition?
Ans: Electron jumps between energy levels.
Q. What is photon emission condition?
Ans: E₂ − E₁ = hν.
Q. What is stationary orbit?
Ans: Orbit with constant energy.
Q. What is principal quantum number?
Ans: Denotes energy level (n).
Q. What is wavelength relation?
Ans: c = νλ.
Q. What is absorption spectrum?
Ans: Dark lines on bright background.
Q. What is emission spectrum?
Ans: Bright lines on dark background.
II. Multiple Choice Questions
Q. Rutherford experiment used:
(a) Electrons
(b) Alpha particles
(c) Protons
(d) Neutrons
Ans: (b)
Q. Bohr model explains:
(a) Stability
(b) Motion
(c) Energy loss
(d) Collision
Ans: (a)
Q. Angular momentum is:
(a) Continuous
(b) Quantized
(c) Zero
(d) Infinite
Ans: (b)
Q. Ground state has:
(a) Highest energy
(b) Lowest energy
(c) Zero energy
(d) Infinite
Ans: (b)
Q. Balmer series lies in:
(a) UV
(b) Visible
(c) IR
(d) X-ray
Ans: (b)
Q. Lyman series lies in:
(a) Visible
(b) UV
(c) IR
(d) Microwave
Ans: (b)
Q. Energy level depends on:
(a) n
(b) m
(c) v
(d) t
Ans: (a)
Q. Rydberg constant unit is:
(a) m
(b) m⁻¹
(c) s
(d) Hz
Ans: (b)
Q. Ionization energy is for:
(a) Excited state
(b) Ground state
(c) Any state
(d) None
Ans: (b)
Q. Spectrum consists of:
(a) Lines
(b) Waves
(c) Particles
(d) Fields
Ans: (a)
Q. Assertion: Rutherford model failed to explain stability. Reason: Accelerating charges radiate energy.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (a)
Q. Assertion: Bohr orbits are stable. Reason: Electrons do not radiate energy in them.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (a)
Q. Assertion: Energy levels are quantized. Reason: Angular momentum is quantized.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (a)
Q. Assertion: Balmer series is visible. Reason: Transitions end at n = 2.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (a)
Q. Assertion: Lyman series is UV. Reason: Transitions end at n = 1.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (a)
Q. Assertion: Ionization energy is highest for ground state. Reason: Electron is closest to nucleus.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (a)
Q. Assertion: Spectrum has discrete lines. Reason: Energy levels are continuous.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (c).
