Physics most important questions with answers

 

Chapter – 1 General QB 1. Discuss the properties of semiconductors. 2. Why does a pure semiconductor behave like an insulator at room temperature? 3. What are donor and acceptor impurities? Give examples. 4. Classify semiconductors on the basis of characteristics. 5. What are Intrinsic and extrinsic semiconductors? 6. Differentiate between P-type and N-type semiconductor. 7. What is Drift and Diffusion current? 8. Define carrier generation and recombination. 9. What is meant by potential barrier across a PN Junction? 10. Define Depletion layer, Threshold voltage and leakage current. 11. Define work function and electron affinity. 12. Differentiate between Ohmic and Schottky contacts 13. What are optoelectronic devices? Classify them. 14. Define Photoluminescence, Cathodoluminescence and Electroluminescence. Twisted QB 1. Derive an expression for density of holes in valence band of an Intrinsic semiconductor 2. Derive an expression for density of electrons in conduction band of an Intrinsic semiconductor 3. Explain the variation of Fermi level with temperature for an intrinsic semiconductor. 4. Obtain expression for majority carriers in n-type semiconductor. 5. Obtain expression for majority carriers in p-type semiconductor. 6. Explain the variation of Fermi level with temperature and concentration for n- type semiconductor. 7. Explain the variation of Fermi level with temperature and concentration for p- type semiconductor. 8. Explain diffusion mechanism in detail. 9. Write a short note on direct recombination. Why is called band-to-band transition? 10. Write a short note on indirect recombination. 11. What changes take place when a p-n junction diode is 1) Forward biased 2) Reverse biased? 12. Explain with diagrams of forward and reverse biasing of a p-n junction. Also plot the V-I curve for both cases 13. Write a short note on Ohmic contacts. 14. Write a short note on Schottky contacts. 15. Explain the basic principle, construction and working with figure and advantages of Light Emitting diode (LED). 16. Explain the basic principle, construction and working with figure and advantages of a photodiode. 17. Write a short note on Zener diode. 18. What is phototransistor? Explain. Important QB 1. Explain with diagrams of forward and reverse biasing of a p-n junction. Also plot the V-I curve for both cases 2. Explain the basic principle, construction and working with figure and advantages of Light Emitting diode (LED). 3. Write a short note on Zener diode. 18. What is phototransistor? Explain. 4. Explain the variation of Fermi level with temperature and concentration for p- type semiconductor. 5. Derive an expression for density of holes in valence band of an intrinsic semiconductor. 6. Derive an expression for density of electrons in conduction band of an intrinsic semiconductor. Chapter – 2 General QB 1. What phenomenon describes the complete absence of electrical resistance in certain materials? 2. Can you describe the unique characteristics exhibited by materials when they enter the superconducting state? 3. How does the presence of a magnetic field affect the behavior of superconductors? 4. What term describes the expulsion of magnetic fields from the interior of a superconductor? 5. Explain how pressure can influence the superconducting properties of a material. 6. How do impurities in a material impact its ability to superconduct? 7. What effect does the mass of isotopes have on the superconducting transition temperature? 8. What theory explains the mechanism behind superconductivity in certain materials? 9. Can you describe the depth to which a magnetic field penetrates into a superconductor? 10. What is the name of the junction used to create superconducting circuits with unique properties? 11. How are Josephson's junctions utilized in superconducting electronics? 12. What are some practical applications of superconductors in everyday life? 13. Describe the behavior of certain materials when they lose all electrical resistance. 14. What are some notable characteristics of materials in the superconducting state? 15. How does the presence of a magnetic field influence the properties of superconductors? 16. What term is used to describe the expulsion of magnetic fields from superconductors? 17. Can you explain how changes in pressure affect a material's superconducting abilities? 18. What impact do impurities have on the superconducting properties of a material? 19. How does the mass of isotopes influence a material's transition to the superconducting state? 20. What theory provides insights into the underlying mechanism of superconductivity? 21. Describe the extent to which a magnetic field can penetrate into a superconductor. 22. How are Josephson's junctions utilized in the construction of superconducting circuits? 23. What are some practical applications of superconductors in various industries? 24. What characteristics distinguish superconducting materials from conventional conductors? 25. How do superconductors behave in the presence of a magnetic field, and how is this behavior utilized in applications? Twisted QB 1. Define phenomena of superconductivity. 2. Discuss the effect of pressure and impurities on the working of superconductor. 3. Explain the effect of isotopic mass on the critical temperature of superconductor. 4. How magnetic field affects the superconducting state? 5. Describe Meissner Effect with neat sketch. 6. What is Meissner effect? Show that Superconducting material is diamagnetic in nature and obtain that magnetic susceptibility of superconductors is -1. 7. Derive the equation for magnetic susceptibility of superconductor. 8. Explain BCS theory with neat sketch. 9. What do you mean by penetration depth? Explain. 10. Explain the working principle of SQUID. 11. Explain Josephson's effect with neat and clean diagram. 12. Discuss various applications of superconductors. 13. Explain working of cryotron switch. 14. Discuss the role of superconductivity in medical science. 15. Write a Short note on: 1) Magnetic Bearings 2) Maglev Vehicles Important QB 1. Explain the effect of isotopic mass on the critical temperature of superconductor. 2. How magnetic field affects the superconducting state? 3. Describe Meissner Effect with neat sketch. 4. What is Meissner effect? Show that Superconducting material is diamagnetic in nature and obtain that magnetic susceptibility of superconductors is -1. 5. Discuss the role of superconductivity in medical science. 6. Write a Short note on: 1) Magnetic Bearings 2) Maglev Vehicles Chapter – 3 General QB 1. Short note on: Properties of ultrasonic waves. 2. Discuss: Piezoelectric method for production of ultrasonic waves 3. Discuss: Magnetostriction method for production of ultrasonic waves 4. Explain different methods of detecting the presence of ultrasonic waves. 5. How ultrasonic waves are used for detecting flows in the specimen? Explain with diagram. 6. Short note on: Ultrasonic cleaning 7. Short note on: Ultrasonic Welding and soldering 8. Short note on: Ultrasonic Drilling 9. How depth of sea or submerged elements is calculated by using ultrasonic waves? Explain with neat sketch. 10. What do you mean by NDT? Why NDT is preferred for testing of material? Explain with advantages. 11. Write advantages of NDT. 12. Explain straight beam type ultrasonic testing. 13. Explain angle beam type ultrasonic testing. . Explain immersion type ultrasonic testing. 15. Explain through transmission type ultrasonic testing Twisted QB 1. What term describes the various forms in which waves can manifest? 2. Can you explain how waves propagate through a medium? 3. What mathematical equation represents the relationship between wave properties? 4. Describe the difference between transverse and longitudinal wave motion. 5. What are ultrasonic waves, and how do they differ from audible sound waves? 6. What are some unique properties of ultrasonic waves compared to audible sound? 7. How are ultrasonic waves generated using the piezoelectric method? 8. Can you explain the magnetostriction method for producing ultrasonic waves? 9. What methods are used to detect the presence of ultrasonic waves? 10. What are some practical applications of ultrasonic waves in various fields? 11. What is non-destructive testing (NDT), and what role does it play in industry? 12. Discuss the advantages of utilizing non-destructive testing methods. 13. How is ultrasound used as a non-destructive testing technique? 14. What are the different types of waves and their characteristics? 15. Can you describe how waves move through a medium? 16. What equation governs the behavior of waves in a given medium? 17. Differentiate between transverse and longitudinal wave vibrations. 18. What distinguishes ultrasonic waves from other forms of waves? 19. How are ultrasonic waves generated using the piezoelectric method? 20. Explain the process of producing ultrasonic waves through magnetostriction. 21. How do we detect the presence of ultrasonic waves in a medium? 22. What practical applications do ultrasonic waves have in various industries? 23. Define non-destructive testing (NDT) and its significance. 24. What benefits does non-destructive testing offer over traditional testing methods? 25. How does ultrasound serve as a tool for non-destructive testing purposes? Important QB 1. Discuss: Piezoelectric method for production of ultrasonic waves 2. Discuss: Magnetostriction method for production of ultrasonic waves 3. How depth of sea or submerged elements is calculated by using ultrasonic waves? Explain with neat sketch. 4. What do you mean by NDT? Why NDT is preferred for testing of material? Explain with advantages. 5. Write advantages of NDT. Chapter – 4 General QB 1. What is full form of LASER? How it differs from ordinary light? 2. Explain: Population Inversion 3. Discuss the characteristics of Laser. 4. Explain: Induced Absorption 5. Explain: Spontaneous Emission 6. Explain: Stimulated Emission 7. Derive the relationship between Einstein's coefficients. 8. Explain construction and working of He-Ne gas laser. 9. Explain energy level diagram for He - Ne gas laser. 10. Discuss advantages and disadvantages of He-Ne gas laser over other types of laser. 11. Explain construction and working of Ruby laser. 12. Explain energy diagram for Ruby laser. 13. Discuss different types of application of laser in Medical field. 14. Laser is very useful in Defense system: Explain this statement. 15. Discuss the role of laser in various technological areas. 16. State different application of laser in communication field. 17. Justify: Laser has unearthed many opportunities for researchers in the field of science. Twisted QB 1. What concept describes the relationship between the emission and absorption of light without mentioning the coefficients? 2. Can you elaborate on the process of light amplification without directly referring to population inversion? 3. Describe the unique characteristics of various devices that emit coherent light without explicitly naming them. 4. How do certain materials amplify light without directly mentioning the types of lasers? 5. What properties define the quality of laser beams without using terms like "monochromaticity" or "coherence"? 6. Can you discuss the visual phenomena associated with laser beams without mentioning "laser speckles"? 7. Explore the diverse applications of coherent light without directly referencing lasers. 8. How do certain theoretical frameworks explain the interaction between matter and radiation without explicitly mentioning Einstein's theory? 9. Discuss the process of light amplification without referring to the mechanisms involved in population inversion. 10. What distinguishes different devices that emit coherent light without explicitly mentioning their classifications? 11. Can you describe the characteristics of laser beams without directly stating their properties like "directionality" or "brightness"? 12. Explore the practical uses of coherent light without directly mentioning its applications in various fields. 13. How do certain principles elucidate the relationship between light and matter without directly referencing Einstein's theory? 14. Discuss the amplification of light without explicitly mentioning the concepts of A and B coefficients. 15. Can you elaborate on the distinct features of light beams without directly stating their properties like "mono-chromaticity" or "coherence"? Important QB 1. How does the interaction between atoms and light lead to the amplification of light waves? 2. Can you describe the distinct characteristics of different devices that emit coherent light? 3. What factors contribute to the quality of laser beams, including their color and uniformity? 4. How are lasers utilized in various scientific, engineering, and medica l applications? 5. What theoretical framework explains the relationship between matter and radiation in the context of laser technology? 6. Can you discuss the process by which light amplification occurs without referring to specific coefficients? 7. What are some key features of laser beams that make them useful in precision applications? 8. How do gas and solid-state lasers differ in their construction and operation? 9. Can you explain the phenomenon of laser speckles without using the term directly? 10. What advantages do lasers offer over traditional light sources in scientific research, engineering, and medical procedures?