Physics Compendium for Biomedical Engineering

Flashcards based on Physics Compendium for Biomedical Engineering lecture notes.

What is a Physical Quantity?

A measurable aspect of a physical phenomenon, expressible as a numerical value with a unit.

What are the fundamental physical quantities?

Length (m), Mass (kg), Time (s), Temperature (K), Electric current (A).

What are some examples of derived physical quantities?

Velocity (m/s), Force (N), Energy (J), Pressure (Pa).

What is a Physical Model?

A simplified but effective representation of how nature behaves.

Give examples of physical models.

Newton’s Laws, Ideal Gas Law, Bohr’s atom.

What is a limitation of physical models?

Every model has a boundary.

What is the rule for addition/subtraction of physical quantities?

You can only add/subtract same types of physical quantities.

What happens when you multiply/divide physical quantities?

It creates new units.

What happens when you multiply a scalar and a vector?

Multiplying a scalar and a vector scales its magnitude.

What is the conclusion based on the observation 'It gets hotter when I rub my hands' and measuring a temperature increase?

Friction increases thermal energy.

Give examples of scalar quantities.

Mass, Temperature, Energy.

Give examples of vector quantities.

Force, Acceleration, Electric field.

What is the Bohr Model of the atom?

Electrons orbit the nucleus in discrete energy levels and jumping between them emits or absorbs photons.

What does the Quantum Model describe about electrons?

Orbitals describe probability clouds.

What is the band structure in conductors?

Valence and conduction bands overlap.

What is the band structure in insulators?

Large band gap.

What is the band structure in semiconductors?

Small band gap, tunable with doping.

What happens during absorption in energy levels?

Electron jumps up a level by absorbing energy.

What happens during emission in energy levels?

Falls down a level, emits a photon.

What characterizes conductors in terms of electrons?

Free electrons (e.g., Cu, Al).

What characterizes insulators in terms of electrons?

Bound electrons (e.g., glass).

How do semiconductors behave in terms of electrical conductivity?

Switch from insulators to conductors via temperature or doping.

What characterizes n-type semiconductors?

Extra electrons (from dopants like P).

What characterizes p-type semiconductors?

Missing electrons or “holes” (from B).

What forms at a PN junction?

Barrier forms between p and n regions.

What is the molecular model of gases?

Kinetic theory describes gases as countless moving particles.

What is temperature?

Average kinetic energy of molecules.

What is pressure?

Force molecules exert on container walls per unit area.

What is the equation for pressure?

P = F / A

What are the characteristics of a solid state of matter?

Fixed shape, low energy.

What are the characteristics of a liquid state of matter?

Takes container shape, higher energy.

What are the characteristics of a gas state of matter?

Free motion, fills volume.

What are the characteristics of a plasma state of matter?

Ionized gas with extreme energy.

What is the Zeroth Law of Thermodynamics?

A = B and B = C implies A = C.

What is the First Law of Thermodynamics?

Energy conservation: ∆U = Q + W

What is the Second Law of Thermodynamics?

Heat flows spontaneously from hot to cold; entropy increases.

What is the Third Law of Thermodynamics?

You can’t reach 0 K in finite steps.

What is the Ideal Gas Equation?

pV = nRT

What is the interpretation of Wien’s Law?

Hotter objects emit more energy at shorter wavelengths (shift toward blue).

What is an electric field?

A region where a charge feels a force; arrows point from + to -.

What types of charges are affected by a magnetic field?

Magnetic field affects moving charges only.

What is the Full Lorentz Force equation?

F⃗ = q(E⃗ + ⃗v × B⃗ )

What is Gauss’ Law (one of Maxwell's Equations)?

∇ · E⃗ = ρ / ε0

What is the statement 'No magnetic monopoles' in Maxwell's Equations?

∇ · B⃗ = 0

What is Faraday’s Law (one of Maxwell's Equations)?

∇ × E⃗ = − ∂B⃗ / ∂t

What is the Amp`ere-Maxwell Law (one of Maxwell's Equations)?

∇ × B⃗ = µ0J⃗ + µ0ε0 ∂E⃗ / ∂t

What is a conclusion from Maxwell's Equations regarding EM waves?

EM waves are self-propagating fields.

What is the equation for the speed of light based on Maxwell's Equations?

c = 1 / √µ0ε0

What is a feature of EM waves (Transverse waves)?

E⃗ and B⃗ are perpendicular to each other and to propagation direction.

What is the polarization of an EM wave?

Direction of electric field oscillation.

Why is shielding important when handling ionizing radiation?

Ionizing radiation (UV, X-rays, γ) can break molecular bonds.