GATE XH flashcards

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

Young's modulus

The ratio of tensile stress to tensile strain within the linear elastic region of a material's stress-strain curve, measured in pascals; a steeper slope indicates a stiffer material.

Carnot efficiency

The maximum possible efficiency of a heat engine operating between a hot reservoir at T_h and a cold reservoir at T_c, equal to 1 minus T_c/T_h with absolute temperatures.

Reynolds number

A dimensionless ratio of inertial to viscous forces, Re = ρvD/μ, used to predict whether pipe flow is laminar, transitional, or turbulent.

Parallel axis theorem

The moment of inertia about any axis equals the moment about a parallel axis through the centroid plus the mass times the square of the perpendicular distance between the axes.

Bernoulli equation

For steady, incompressible, inviscid flow along a streamline, pressure plus half the density times velocity squared plus density times gravitational potential energy per volume stays constant.

Integrating factor

For a first-order linear differential equation y′ + Py = Q, the multiplier e raised to the integral of P dx, which converts the left side into an exact derivative.

Duty cycle

The fraction of one period during which a periodic signal is in its active or high state, usually expressed as a percentage of the total period.

De Morgan's laws

Boolean identities stating that the complement of a product equals the sum of the complements, and the complement of a sum equals the product of the complements.

Nyquist sampling theorem

A signal limited to frequencies below f_max can be reconstructed exactly only if sampled at a rate strictly greater than twice f_max.

Shannon capacity formula

The maximum error-free data rate of a noisy channel, C = B log₂(1 + S/N), where B is bandwidth and S/N the signal-to-noise power ratio.

Amdahl's law

Gives overall speedup as one divided by the sum of the serial fraction and the parallel fraction divided by its speedup; limited by the non-parallel portion.

Cache miss penalty

The extra time required to fetch a requested block from a lower memory level when it is absent from the cache, added to hit time weighted by miss rate.

TCP slow start

A congestion control phase in which the congestion window increases by roughly one maximum segment size per acknowledged round trip, producing exponential growth until a threshold or loss.

XOR parity property

The exclusive-OR of a set of bits is one when the number of ones is odd and zero when even, making it the standard building block for parity generation and checking.

Binary search complexity

Searching a sorted array by repeatedly halving the interval takes logarithmic time in the number of elements and constant extra space if implemented iteratively.

Floor Area Ratio

The total built-up floor area of all floors divided by the plot area; it caps development intensity and is fixed by local building regulations.

Ground coverage

The area of the building footprint projected on the ground divided by the plot area, expressed as a percentage and limited by zoning bye-laws.

Drawing scale 1:100

One unit measured on the drawing represents one hundred of the same units on site; areas on such a drawing correspond to ten thousand times the drawn area.

Setback

The mandatory open distance between the building line and the plot boundary, prescribed by local bye-laws to ensure light, ventilation, and fire access.

M25 concrete

A concrete mix designation whose characteristic compressive cube strength is 25 newtons per square millimetre when tested at twenty-eight days of curing.

Modular brick size

The standard Indian modular brick measures 190 by 90 by 90 millimetres; adding mortar joints gives a nominal module of 200 by 100 by 100 millimetres.

Load-bearing versus framed

In load-bearing construction, walls carry loads directly to the foundation; in framed construction, beams and columns carry loads, letting walls be non-structural partitions.

Sun path diagram

A polar chart plotting solar altitude and azimuth for a given latitude across seasons, used to plan shading, orientation, and daylighting of buildings.

Ideal gas law

The relation PV = nRT linking pressure, volume, amount in moles, and absolute temperature through the universal gas constant, valid for ideal gases.

First law of thermodynamics

Energy conservation for a system: the change in internal energy equals heat added to the system minus work done by the system on its surroundings.

pH definition

The negative base-ten logarithm of hydrogen ion concentration in moles per litre; a change of one pH unit means a tenfold change in acidity.

First-order half-life

For a reaction whose rate depends linearly on one reactant, the half-life equals the natural logarithm of two divided by the rate constant and is independent of concentration.

Orbital speed

For a circular orbit of radius r around a body of mass M, the speed is the square root of the gravitational constant times M divided by r.

Total internal reflection

Occurs when light travelling from a denser to a rarer medium strikes the interface beyond the critical angle, so no refracted ray emerges and all light reflects.

Michaelis constant Km

The substrate concentration at which an enzyme-catalysed reaction proceeds at half its maximum velocity; a low value indicates high substrate affinity.

DNA base pairing

Adenine pairs with thymine through two hydrogen bonds and guanine pairs with cytosine through three; RNA substitutes uracil for thymine.

Snell's law

Relates angles of incidence and refraction at an interface: the product of refractive index and sine of the angle is equal on both sides of the boundary.