Chapter 9: Atomic and Nuclear Physics — Online MCQ Test
PHYSICS · CLASS 12th · Tamil Nadu State Board
Practice Chapter 9: Atomic and Nuclear Physics with a free chapter-wise online MCQ test.
This chapter covers: Focusing on subatomic physics this chapter details Rutherford and Bohr atomic models alongside hydrogen spectra. Students study nuclear structure binding energy radioactivity nucle....
AI-generated questions from basic to board-exam level, with instant results and explanations.
Chapter 9: Atomic and Nuclear Physics — Important Questions & Answers
Who proposed the nuclear model of the atom based on the gold foil experiment?
- A. J. J. Thomson
- B. Ernest Rutherford
- C. Niels Bohr
- D. James Chadwick
Answer: B. Ernest Rutherford
Rutherford proposed the nuclear model after analyzing the scattering of alpha particles by thin gold foil. The experiment showed that most of the atom is empty space with a small, dense nucleus.
Rutherford proposed the nuclear model after analyzing the scattering of alpha particles by thin gold foil. The experiment showed that most of the atom is empty space with a small, dense nucleus.
Which of the following is the correct expression for the radius of the nth orbit of hydrogen atom in Bohr model?
- A. r_n = n^2 a_0
- B. r_n = a_0 / n^2
- C. r_n = n a_0^2
- D. r_n = 2n a_0
Answer: A. r_n = n^2 a_0
In the Bohr model, the radius of the nth orbit is proportional to n squared. Here, a0 is the Bohr radius for the first orbit.
In the Bohr model, the radius of the nth orbit is proportional to n squared. Here, a0 is the Bohr radius for the first orbit.
If an alpha particle is scattered through a very large angle in Rutherford’s experiment, it indicates that:
- A. the atom is entirely empty
- B. the nucleus is positively charged and very small
- C. electrons have large mass
- D. the atom has no nucleus
Answer: B. the nucleus is positively charged and very small
Large-angle scattering occurs when the alpha particle comes close to the compact, positively charged nucleus. This supports Rutherford’s nuclear model.
Large-angle scattering occurs when the alpha particle comes close to the compact, positively charged nucleus. This supports Rutherford’s nuclear model.
Which of the following is the most stable nucleus among the given options, based on binding energy per nucleon concept?
- A. A nucleus with very low binding energy per nucleon
- B. A nucleus with maximum binding energy per nucleon
- C. A nucleus with zero mass defect
- D. A nucleus with equal protons and neutrons only
Answer: B. A nucleus with maximum binding energy per nucleon
A higher binding energy per nucleon indicates a more tightly bound and therefore more stable nucleus. Stability is related to how strongly nucleons are held together.
A higher binding energy per nucleon indicates a more tightly bound and therefore more stable nucleus. Stability is related to how strongly nucleons are held together.
Which of the following is the best reason why controlled nuclear fission is used in nuclear reactors and not uncontrolled chain reaction?
- A. To increase the number of neutrons infinitely
- B. To keep the reaction rate steady and prevent explosion
- C. To convert mass directly into electrons
- D. To produce only alpha particles
Answer: B. To keep the reaction rate steady and prevent explosion
A nuclear reactor uses control rods to absorb excess neutrons and maintain a steady chain reaction. This prevents the reaction from becoming explosive.
A nuclear reactor uses control rods to absorb excess neutrons and maintain a steady chain reaction. This prevents the reaction from becoming explosive.