GIKI Test flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Ohm's law

For a resistive element, voltage equals current times resistance (V = IR); power dissipated is VI = I²R = V²/R.

Thevenin's theorem

Any linear two-terminal network can be replaced by an equivalent voltage source V_th in series with a resistance R_th.

Series RLC resonance

Resonance occurs at f₀ = 1/(2π√(LC)); at that frequency the inductive and capacitive reactances cancel and impedance is purely resistive.

Three-phase power

For a balanced three-phase load, total real power is P = √3 V_L I_L cos φ, where φ is the phase angle between phase voltage and current.

Binary search complexity

Binary search operates on a sorted array and halves the search interval each step, giving O(log n) time; linear search is O(n).

TCP versus UDP

TCP is connection-oriented, reliable, and ordered; UDP is connectionless and does not guarantee delivery, ordering, or duplicate suppression.

Hash table load factor

Load factor α equals stored entries divided by number of buckets; average lookup is O(1) when α is kept moderate, using chaining or open addressing.

Two's complement range

An n-bit two's complement integer ranges from −2^(n−1) to 2^(n−1)−1; negation is performed by inverting all bits and adding one.

Reynolds number

Re = ρvD/μ compares inertial to viscous forces; pipe flow is typically laminar below about 2000 and turbulent above about 4000.

Bernoulli equation

Along a streamline in steady, incompressible, inviscid flow, P + ½ρv² + ρgh remains constant, linking pressure, speed, and elevation.

First law of thermodynamics

Energy is conserved: ΔU = Q − W, where Q is heat added to the system and W is work done by the system.

Beam bending stress

Normal stress in bending is σ = My/I, where M is the bending moment, y the distance from the neutral axis, and I the second moment of area.

Euler buckling load

For a pin-ended column, the critical buckling load is P_cr = π²EI/L², where E is Young's modulus, I the second moment of area, and L the length.

Carnot efficiency

The maximum efficiency of a heat engine between reservoirs at T_H and T_C is η = 1 − T_C/T_H, with temperatures expressed in kelvin.

Continuity equation

For steady incompressible flow through a duct, A₁v₁ = A₂v₂, so velocity increases where the cross-sectional area decreases.

Atomic packing factor

The fraction of unit-cell volume occupied by atoms is 0.74 for FCC and HCP and 0.68 for BCC; FCC contains four atoms per unit cell.

Hall–Petch relation

Yield strength increases as grain size decreases, described by σ_y = σ₀ + k/√d, where d is the average grain diameter.

Fick's first law

Diffusion flux is proportional to the concentration gradient: J = −D(dC/dx), where D is the diffusion coefficient and the negative sign indicates down-gradient flow.

Gibbs phase rule

For a system at equilibrium, degrees of freedom F = C − P + 2, where C is the number of components and P the number of phases.

Arrhenius equation

Rate constant k = A e^(−E_a/RT); a larger activation energy E_a makes the reaction rate more sensitive to temperature changes.

First-order half-life

For a first-order reaction, concentration decays as C = C₀e^(−kt) and the half-life is t₁/₂ = ln2/k, independent of initial concentration.

Le Chatelier's principle

A system at equilibrium shifts to counteract an imposed change; for gases, increasing pressure favors the side with fewer moles.

Heat exchanger effectiveness

Effectiveness ε is the ratio of actual heat transfer to the maximum possible heat transfer for given inlet temperatures and flow rates.

Simply supported beam moment

A simply supported beam under a uniformly distributed load w over span L has maximum bending moment wL²/8 at midspan.

Axial deformation formula

A prismatic member under axial load P deforms by δ = PL/(AE), where L is length, A cross-sectional area, and E Young's modulus.

Darcy's law

Groundwater flow velocity through soil is v = ki, where k is hydraulic conductivity and i is the hydraulic gradient Δh/L.

Break-even quantity

The output level at which total revenue equals total cost is Q = Fixed Costs / (Price − Variable Cost per Unit).

Net present value

NPV discounts all future cash flows to the present at rate r and subtracts the initial investment; a positive NPV justifies the project.

CAPM required return

The capital asset pricing model gives required return = R_f + β(R_m − R_f), where β measures systematic risk relative to the market.

Projectile range

For launch speed u at angle θ on level ground, horizontal range is R = u² sin2θ/g; maximum range occurs at 45 degrees.

pH definition

pH = −log[H⁺]; a one-unit decrease in pH corresponds to a tenfold increase in hydrogen-ion concentration.

Precision and recall

Precision = TP/(TP+FP) measures correctness of positive predictions; recall = TP/(TP+FN) measures coverage of actual positives.