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