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Nanoelectronics and quantum effects – MCQs – EE

1. Nanoelectronics is the branch of electronics that deals with devices operating at dimensions below:

(A) 100 nanometers


(B) 1 micrometer


(C) 1 millimeter


(D) 100 micrometers



2. Quantum effects become significant in devices when their dimensions are comparable to:

(A) Electron’s de Broglie wavelength


(B) Device width


(C) Magnetic field intensity


(D) Current magnitude



3. The quantum confinement effect occurs when:

(A) Electrons are confined to dimensions smaller than their wavelength


(B) The temperature is very high


(C) The magnetic field is zero


(D) Current is constant



4. A quantum well confines electrons in:

(A) One dimension


(B) Two dimensions


(C) Three dimensions


(D) Zero dimensions



5. A quantum wire confines electrons in:

(A) Two dimensions


(B) One dimension


(C) Three dimensions


(D) No dimensions



6. A quantum dot confines electrons in:

(A) All three dimensions


(B) Two dimensions


(C) One dimension


(D) No confinement



7. The energy levels in a quantum dot are:

(A) Discrete


(B) Continuous


(C) Random


(D) Infinite



8. In nanoelectronic devices, tunneling current occurs due to:

(A) Quantum mechanical penetration through potential barriers


(B) Thermal expansion


(C) Magnetic induction


(D) Electron reflection



9. Coulomb blockade is a phenomenon observed in:

(A) Single-electron transistors


(B) MOSFETs


(C) PN junction diodes


(D) Zener diodes



10. A single-electron transistor (SET) controls current by:

(A) Movement of individual electrons


(B) Magnetic field variation


(C) Light intensity


(D) Temperature changes



11. Ballistic transport in nanoelectronics means:

(A) Electrons move without scattering


(B) Electrons are trapped


(C) Electrons lose energy continuously


(D) Electrons collide frequently



12. The tunneling probability increases when:

(A) Barrier width and height decrease


(B) Barrier width increases


(C) Barrier height increases


(D) Electron energy decreases



13. Quantum capacitance arises due to:

(A) Finite density of electronic states in nanostructures


(B) Dielectric breakdown


(C) Surface charge accumulation


(D) Magnetic flux linkage



14. The quantum Hall effect is observed under:

(A) Low temperatures and strong magnetic fields


(B) High temperatures


(C) Zero magnetic field


(D) High humidity



15. Resonant tunneling diodes (RTDs) operate based on:

(A) Quantum tunneling through double potential barriers


(B) Magnetic field coupling


(C) Photoelectric emission


(D) Thermionic emission



16. The bandgap of a semiconductor nanocrystal:

(A) Increases as particle size decreases


(B) Decreases as particle size decreases


(C) Remains constant


(D) Becomes zero



17. Quantum interference occurs due to:

(A) Superposition of electron wavefunctions


(B) Electric noise


(C) Magnetic flux only


(D) Lattice vibration



18. The density of states (DOS) in a quantum dot is:

(A) Discrete peaks


(B) Continuous


(C) Constant


(D) Infinite



19. Spintronics utilizes:

(A) Electron spin as well as charge


(B) Proton spin


(C) Electric current only


(D) Thermal energy



20. Graphene-based nanoelectronics exhibit:

(A) High carrier mobility and ballistic transport


(B) Low conductivity


(C) High resistivity


(D) Poor switching speed



21. Moore’s Law predicts that transistor density doubles approximately every:

(A) 18–24 months


(B) 5 years


(C) 10 years


(D) 6 months



22. Quantum dots are often called:

(A) Artificial atoms


(B) Artificial molecules


(C) Nanoelectrodes


(D) Nanowires



23. Quantum tunneling limits the miniaturization of:

(A) CMOS transistors


(B) Resistors


(C) Capacitors


(D) Inductors



24. In nano-MOSFETs, the short-channel effect is more pronounced because:

(A) Gate control weakens as channel length decreases


(B) Gate capacitance increases


(C) Source voltage drops


(D) Oxide thickness increases



25. Quantum dots are used in LEDs because they:

(A) Emit light of tunable wavelengths


(B) Reflect light


(C) Absorb infrared radiation


(D) Reduce current flow



26. Quantum tunneling devices can operate at:

(A) Very high speeds


(B) Low temperatures only


(C) Very low voltages


(D) High magnetic fields only



27. Quantum computing relies on:

(A) Superposition and entanglement of quantum states


(B) Binary switching


(C) Thermal noise reduction


(D) Magnetic field control only



28. Quantum wires are used in optoelectronics for:

(A) High-speed signal transmission and light emission


(B) Heat insulation


(C) Magnetic shielding


(D) Optical filtering only



29. The main limitation of nanoelectronic devices is:

(A) Quantum leakage and fabrication complexity


(B) High power loss


(C) Low speed


(D) High size



30. The future of nanoelectronics aims for:

(A) Faster, smaller, energy-efficient, and quantum-based devices


(B) Larger and slower devices


(C) Manual operation systems


(D) High-temperature conductors



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