GATE IN flashcards

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

Thevenin's theorem

Any linear two-terminal network can be replaced by a single voltage source V_th in series with a resistance R_th, where V_th is the open-circuit voltage and R_th the equivalent resistance with sources killed.

Carnot efficiency

The maximum efficiency of a heat engine operating between hot and cold reservoirs at absolute temperatures T_H and T_C is 1 − T_C/T_H, achieved only by a reversible cycle.

Reynolds number

A dimensionless ratio of inertial to viscous forces, Re = ρVD/μ. Values below roughly 2300 indicate laminar pipe flow; above roughly 4000, turbulent flow.

Maximum power transfer

A source delivers maximum power to a load when the load resistance equals the source's Thevenin resistance; the efficiency at that point is only 50 percent.

Bernoulli's equation

For steady, incompressible, inviscid flow along a streamline, pressure plus kinetic and potential energy terms per unit volume stays constant: P + ½ρV² + ρgz = constant.

RC time constant

The product τ = RC sets how fast a capacitor charges or discharges through a resistor; after one τ the voltage has moved about 63.2 percent toward its final value.

Three-way TCP handshake

Connection setup in TCP uses SYN, then SYN-ACK, then ACK, synchronising sequence numbers and confirming both endpoints are ready before data transfer begins.

Subnet host count

For an IPv4 subnet with prefix length p, usable host addresses equal 2^(32 − p) − 2, because the all-zeros network address and all-ones broadcast address are reserved.

Amdahl's law

Speedup from parallelisation is 1/((1 − f) + f/s), where f is the parallelisable fraction and s the speedup of that fraction; serial parts limit total gain.

Third normal form

A relation is in 3NF when it is in 2NF and has no transitive dependency of a non-key attribute on the primary key, reducing redundancy and update anomalies.

Binary search tree

A binary tree where every left descendant key is smaller and every right descendant key larger than the node; search is O(log n) when balanced, O(n) when degenerate.

Digital signature

A value produced by hashing a message and encrypting the hash with the sender's private key, letting anyone verify authenticity and integrity using the public key.

Floor Area Ratio

FAR equals total floor area of all storeys divided by plot area. It caps building bulk under local bye-laws and is distinct from ground coverage.

Stair proportion rule

Comfortable stairs satisfy 2 × riser + tread ≈ 600–640 mm, with risers typically 150–190 mm and treads 250–300 mm for public buildings.

Daylight factor

The ratio of indoor illuminance at a reference point to simultaneous unobstructed outdoor horizontal illuminance, expressed as a percentage independent of sky brightness.

Cantilever bending moment

A cantilever fixed at one end and free at the other develops hogging, negative bending moment at the support under downward load, with maximum deflection at the free end.

M25 concrete grade

The designation M25 denotes concrete with a characteristic cube compressive strength of 25 N/mm² measured at 28 days, used in structural design per IS 456.

Ideal gas law

PV = nRT relates pressure, volume, amount and absolute temperature of an ideal gas, with R = 8.314 J mol⁻¹ K⁻¹; one mole occupies about 22.4 L at STP.

pH definition

pH is the negative base-10 logarithm of hydrogen ion concentration in moles per litre; a change of one pH unit means a tenfold change in acidity.

Radioactive half-life

The time in which half the nuclei of a sample decay; remaining amount follows N = N₀e^(−λt) with decay constant λ = ln 2 divided by half-life.

Snell's law

Refraction at an interface obeys n₁ sin θ₁ = n₂ sin θ₂, where n is refractive index and θ is the angle from the normal; it underlies lenses and total internal reflection.

Mendelian 3:1 ratio

A monohybrid cross of two true-breeding parents differing in one trait yields an F2 phenotypic ratio of three dominant to one recessive, with genotype ratio 1:2:1.

Accounting equation

Assets equal liabilities plus equity. Every transaction affects at least two accounts so the equation always stays balanced under double-entry bookkeeping.

Break-even quantity

The output at which total revenue equals total cost, computed as fixed cost divided by contribution margin per unit (price minus variable cost per unit).

Net present value

NPV discounts all expected cash flows at the required rate and subtracts the initial outlay; a positive NPV means the project adds value.

Current ratio

Current assets divided by current liabilities, a liquidity measure of short-term debt-paying ability; a quick ratio excludes inventory for a stricter test.

Input tax credit

Under GST, tax paid on inputs and services can be set off against tax payable on output supplies, preventing cascading of tax across the supply chain.

Rasa theory

From the Natyashastra, rasa is the aesthetic emotion evoked in a prepared spectator; nine rasas include shringara, hasya, karuna, raudra, veera and adbhuta.

Eight classical dance forms

The Sangeet Natak Akademi recognises Bharatanatyam, Kathak, Kathakali, Kuchipudi, Odissi, Manipuri, Mohiniyattam and Sattriya as India's classical dance forms.

One-point perspective

A drawing convention in which parallel lines receding from the viewer converge at a single vanishing point on the horizon, giving the illusion of depth.

Categorical imperative

Kant's supreme moral principle: act only on maxims you could will as universal law, and treat persons always as ends, never merely as means.

Cogito ergo sum

Descartes' conclusion that the act of thinking proves the thinker exists, providing a foundation that survives even the most radical methodological doubt.

Phoneme versus morpheme

A phoneme is the smallest sound unit that distinguishes meaning, such as /p/ versus /b/; a morpheme is the smallest unit that carries meaning, such as 'un-' or '-ed'.