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Stern and Gerlach Experiment - Lecture Notes For Atomic Physics

Consolidated Question Bank - Atomic and Nuclear Physics 23BPH5C2 2025

UNIT - I
PART A - 2 MARK QUESTIONS

1. Mention any two drawbacks of Bohr's atom model.
2. What is meant by spatial quantization?
3. Differentiate between LS and JJ coupling.

4. State Pauli's exclusion principle.

5. Define Bohr Magneton and State its formula.

6. What is the outcome of Stern-Gerlach experiment?

7. Write any two selections rules.

PART B - 5 MARK QUESTIONS

1. Explain the Vector atom model and list the associated quantum numbers.
2. Describe the Stern-Gerlach experiment and its significance.
3. Derive the expression for magnetic dipole moment due to orbital and spin motion of the electron.

4. State and explain the selection rules and intensity rule for atomic transitions.

PART C - 10 MARK QUESTIONS

1. Explain the Vector Atom Model in detail. Discuss the quantum numbers associated with it and their significance.
2. Describe the Stern–Gerlach experiment.
3. Discuss in detail L–S coupling and J–J coupling schemes. 

UNIT - II

PART A - 2 MARK QUESTIONS

1. What is meant by excitation potential?

2. Define ionization potential.

3. What are spectral terms? Give an example.

4. Write the notation for the term symbol of the ground state of sodium.

5. What is Zeeman effect?

6. State Larmor’s theorem.

7. Differentiate between normal and anomalous Zeeman effect.

8. What is Paschen–Back effect?

9. What is the Stark effect?

PART B - 5 MARK QUESTIONS

1. Distinguish between excitation potential and ionization potential.
2. Describe Davis and Goucher’s method for the measurement of excitation and ionization potentials.

3. Explain spectral terms and term symbols with suitable examples.

4. Describe the fine structure of sodium D-lines.

5. Write a note on the Paschen–Back effect.

PART C - 10 MARK QUESTIONS

1. Describe the Zeeman effect. State Larmor's theorem and explain the quantum mechanical explanation of the normal Zeeman effect.

UNIT - III

PART A - 2 MARK QUESTIONS

1. State Geiger-Nuttal law.

2. List any two properties of alpha particles.

3. Define nuclear isomerism.

4. What is meant by internal conversion?

5. Write note on non-conservation of parity in weak interactions.

6. What are the characteristics of beta rays?

7. State any two properties of gamma rays.

PART B - 5 MARK QUESTIONS

1. State and Explain Geiger-Nuttal law.

2. Write short notes on the properties of alpha, beta, and gamma rays.

3. Explain Gamow's theory of alpha decay.

4. Describe the beta-ray spectrum and explain how it led to the prediction of the neutrino.

5. Write note on internal conversion.

6. Explain nuclear isomerism with an example.

PART C - 10 MARK QUESTIONS

1. Explain the properties of alpha, beta, and gamma rays. How are they distinguished experimentally?

2. Describe Geiger–Nuttall law. Discuss Gamow’s theory of alpha decay and explain how it accounts for the law.

3. Discuss the beta ray spectrum. Explain the neutrino theory of beta decay and how it resolves the conservation issues.

4. What is nuclear isomerism? Explain internal conversion and discuss the violation of parity in weak interactions.

UNIT - IV

PART A - 2 MARK QUESTIONS

1. State any two conservation laws applicable to nuclear reactions.

2. What is meant by Q-value of a nuclear reaction?

3. Define threshold energy.

4. What is scattering cross section?.

5. What is artificial radioactivity? Give an example.

6. Mention any two applications of radio isotopes.

7. Differentiate between thermal neutrons and fast neutrons.

PART B - 5 MARK QUESTIONS

1. State and explain the conservation laws involved in a nuclear reaction.

2. Derive the Q-value equation for a nuclear reaction. What does a positive or negative Q value indicates?

3. Define threshold energy. Derive an expression of an endoergic nuclear reaction.

4. What is artificial radioactivity? Explain with a suitable reaction. 

5. Compare the liquid drop model and shell model of the nucleus.

PART C - 10 MARK QUESTIONS

1. Derive the Q-value equation for a nuclear reaction explain its significance.

2. Explain the concept of threshold energy. Derive the expression for threshold energy in an endoergic reaction.

3. Discuss the liquid drop model of the nucleus. Explain how it accounts for nuclear binding energy and fission.

4. Explain the shell model of the nucleus. How does it account for magic numbers and nuclear properties?.

UNIT - V
PART A - 2 MARK QUESTIONS

1. What are elementary particles? Give two examples.
2. Name the four fundamental interactions in nature.
3. What is isospin?

4. Define the strangeness quantum number.

5. What are quarks? Name any two types.

6. What is meant by latitude effect in cosmic rays?

7. Differentiate between primary and secondary cosmic rays.

PART B - 5 MARK QUESTIONS

1. Classify the elementary particles based on their interaction types.
2. Explain the concept of isospin and strangeness with suitable examples.
3. State the conservation laws obeyed in particle interactions.

4. Write a short note on quark model.

5. Describe the latitude and longitude effects of cosmic rays.

PART C - 10 MARK QUESTIONS

1. Classify the elementary particles. Explain their interaction and properties with suitable example.
2. Discuss the quantum numbers of elementary particles. Explain the significance of isospin and strangeness.
3. Explain the quark model of elementary particles. How do quarks combine to form hadrons?

4. Describe the discovery of cosmic rays. Differentiate between primary and secondary cosmic rays. Explain the latitude and altitude effects.

Unit V : Laser 2 Marks

 1. What is stimulated emission?

When an excited electron in an atom or molecule returns to a lower energy level due to interaction with an incoming photon, it emits a second photon with the same energy, phase, direction, and polarization. This is called stimulated emission. 

2. What is population inversion?

Population inversion is a condition where more atoms or molecules are in an excited state than in the ground state. This is usually achieved using external energy (optical pumping).

3. Define optical pumping.

The process of supplying energy to the laser medium (using light, electrical discharge, or chemical reaction) to excite electrons to higher energy levels in order to achieve population inversion is called optical pumping.

4. What are metastable states?

Metastable states are energy levels where excited electrons stay longer than usual. The longer lifetime allows more atoms to accumulate in this state, aiding in achieving population inversion.

5. Write note amplification of light in laser.

As light photons travel through the medium, they stimulate more emissions, resulting in amplification of light. The chain reaction of stimulated emission increases the intensity of light.

6. What is coherence of light?

Light is said to be coherent, when the photons are having constant phase difference in time and space. 

7. What is an optical resonator?

A pair of mirrors placed at both ends of the laser medium forms an optical resonator. One mirror is fully reflective and the other is partially reflective, allowing some light to escape as a laser beam. The resonator helps amplify the light and ensure that only certain directions and wavelengths are sustained.

Fresnel Assumptions

1. The entire wavefront can be divided into a large number of elements or zones of small area such that each of these elements acts as a source of secondary waves emitting waves in all directions.
2. The effect at any point “O” will be the resultant of the secondary wavelets reaching “O” from various elements of the wavefront.
3. The effect at any point due to a particular zone depends on (a). the distance of point from the zone. (b). the inclination of the point with reference to zone under consideration.(c). area of the zone.