7 Band theory

What is the purpose of a PN Junction in electronics?

• To generate alternating current

• To allow current flow in one direction while blocking it in the other

• To amplify voltages in a circuit

• To create a superconducting state

What is the characteristic temperature below which superconductivity occurs?

• 0 K

• 200 K

• 20 K

• 273 K

How do electrons form Cooper pairs in the superconducting state?

• By experiencing a net attraction toward positive ions in the lattice

• By becoming stationary within the lattice

• By repelling each other due to like charges

• By interacting with photons in the lattice

What is the function of a Schottky Barrier in semiconductor devices?

• To induce superconductivity in the material

• To generate alternating magnetic fields

• To amplify current flow in a circuit

• To create a potential barrier between a metal and a semiconductor

What is the primary benefit of integrated circuits in modern technology?

• Lower production costs

• Higher energy consumption

• Enhanced conductivity and resistance

• Miniaturization and processing speed

What does the Drude model assume about electrons in metals?

• Electrons are non-interacting and free to move.

• Electrons strongly interact with each other.

• Quantum effects in metals are accurately predicted.

• It was developed after quantum mechanics.

What is true about the wave function of a hydrogen atom?

• It does not depend on the electron's coordinates.

• It represents the strong interaction between two hydrogen atoms.

• It describes the electron's probability distribution.

• It provides no information about the electron's energy or momentum.

What is true about semiconductors?

• Holes move opposite to the electric field.

• Intrinsic semiconductors have more electrons than holes.

• Arsenic doping in silicon needs 0.05 eV for conductivity.

• Carbon and germanium are impurity semiconductors.

What occurs when indium is added to silicon?

• It creates donor levels and an n-type semiconductor.

• It increases the number of electrons in the conduction band.

• It introduces acceptor levels and forms a p-type semiconductor.

• It results in a compound semiconductor with equal atoms of silicon and indium.

In an npn transistor with a heavily doped emitter and thin base, what is the result?

• Lower output current than input.

• Lower output current than input.

• Output voltage lower than input.

• Higher output power due to increased current and voltage.