COMEDK UGET key terms

A measure of how strongly a body resists changes to its rotational motion, equal to the sum of each mass element multiplied by the square of its distance from the axis.

The turning effect of a force about a point or axis, calculated as force multiplied by the perpendicular distance from the axis to the force's line of action.

The rotational analogue of linear momentum, equal to moment of inertia times angular velocity for a rigid body rotating about a fixed axis; conserved when net external torque is zero.

The minimum speed an object needs at a planet's surface to leave its gravitational field permanently without further propulsion, equal to the square root of 2GM/R.

The speed required for a satellite to maintain a stable circular orbit at a given radius from a central body, equal to the square root of GM/r.

Three empirical rules describing planetary motion: orbits are ellipses with the Sun at one focus, equal areas are swept in equal times, and the square of the period is proportional to the cube of the semi-major axis.

The change in observed frequency of a wave when the source and observer move relative to each other, producing a higher pitch on approach and a lower pitch on recession.

A wave pattern formed by two identical waves travelling in opposite directions, producing fixed nodes and antinodes; its allowed frequencies depend on the length and boundary conditions of the medium.

The large-amplitude response that occurs when a system is driven at one of its natural frequencies, where energy transfer from the driving source is maximal.

A dimensionless number describing how underdamped an oscillator is, equal to the resonant frequency divided by the bandwidth of the resonance curve; higher values mean slower energy loss.

The emission of electrons from a metal surface when light above a threshold frequency strikes it, showing that light delivers energy in discrete quanta rather than continuously.

The minimum energy needed to remove an electron from the surface of a particular metal; it sets the threshold frequency below which no photoelectric emission occurs.

The wavelength associated with a moving particle, equal to Planck's constant divided by the particle's momentum; it explains electron diffraction and quantised atomic energy levels.

The rule that position and momentum of a particle cannot both be known with arbitrary precision; the product of their uncertainties is at least Planck's constant divided by four pi.

A changing magnetic flux through a circuit induces an electromotive force proportional to the rate of change of that flux; the induced current opposes the change.

The direction of an induced current is such that its own magnetic field opposes the change in flux that produced it, a consequence of energy conservation.

The property of a coil by which a changing current in it induces an opposing electromotive force in the same coil, measured in henries and depending on geometry and core material.

Two circuit rules: the sum of currents entering a junction equals the sum leaving, and the algebraic sum of potential differences around any closed loop is zero.

A four-resistor network used to measure an unknown resistance; the bridge is balanced, giving zero galvanometer deflection, when the ratio of two arms equals the ratio of the other two.

A measuring instrument that compares potential differences without drawing current from the circuit under test, giving more accurate results than a voltmeter for electromotive force measurement.

The resistance within a source such as a cell or battery that causes its terminal voltage to fall below its electromotive force as current is drawn.

A solution that resists changes in pH when small amounts of acid or base are added, typically made from a weak acid with its conjugate base or a weak base with its conjugate acid.

A relationship giving the pH of a buffer as pKa plus the logarithm of the ratio of conjugate base concentration to weak acid concentration.

pH measures hydrogen ion concentration on a logarithmic scale; pKa is the negative logarithm of an acid's dissociation constant and indicates the pH at which it is half-dissociated.

When a system at equilibrium is disturbed by a change in concentration, pressure, or temperature, it shifts in the direction that partially counteracts the disturbance.

The ratio of product concentrations to reactant concentrations, each raised to its stoichiometric coefficient, for a reversible reaction at equilibrium; it varies with temperature only.

When a hydrogen halide adds to an unsymmetrical alkene, the hydrogen attaches to the carbon bearing more hydrogens, so the halogen ends up on the more substituted carbon.

The mixing of atomic orbitals of similar energy to form equivalent new orbitals, explaining the geometry of molecules such as tetrahedral methane or planar ethene.

A form of isomerism where molecules have the same molecular formula and connectivity but differ in the three-dimensional arrangement of atoms in space, including optical and geometric isomers.

A function has a limit L at a point if its values approach L from both sides; it is continuous there if the limit exists and equals the function's value at that point.

Standard formulas for finding derivatives, including the product rule, quotient rule, chain rule, and derivatives of trigonometric, exponential, and logarithmic functions.

The limit of a sum of areas under a curve between two limits, evaluated using the fundamental theorem of calculus as the difference of an antiderivative at the endpoints.

The region between a function's graph and the x-axis over an interval, computed by integration; areas below the axis count as negative unless absolute value is taken.

Points where a function reaches a local high or low value, found by setting the first derivative to zero and checking the sign change of the derivative or the second derivative test.

A structure is in equilibrium when the total work done by all forces during any small imagined displacement consistent with the supports is zero.

The condition in which a structure or body has zero net force and zero net moment acting on it, so it remains at rest.

A sketch showing a body isolated from its surroundings with every external force and moment drawn as a vector, used to set up equilibrium equations.

A proportion of about 1.618 in which the ratio of the whole to the larger part equals the ratio of the larger part to the smaller, historically used to analyse pleasing architectural proportions.

Scale is the size of an element relative to a known reference such as the human body; proportion is the harmonious relationship between the dimensions of parts and the whole.

A design method using a standard dimensional unit so that building components and spaces fit together without cutting or waste, common in prefabricated construction.

A regular arrangement of columns and beams at fixed spacing that carries building loads and organises the plan and facade into repeating bays.

A wall that supports loads from floors and roof above in addition to its own weight, so it cannot be removed without providing an alternative structural path.

A beam or slab fixed at one end and free at the other, carrying load through bending with maximum moment at the support and zero moment at the free end.

A balanced arrangement of parts about an axis or centre, used in architecture to give buildings visual stability, formality, and legibility.

A traditional Indian system of architecture and spatial planning that prescribes orientation, room placement, and proportions based on directional and elemental principles.

The arrangement, size, and pattern of windows and openings in a building facade, affecting daylight, ventilation, appearance, and thermal performance.

A circular chart plotting the Sun's apparent position across the sky for a given latitude through the year, used to plan shading and orientation.

A drawing technique that shows three-dimensional objects on a flat surface so that parallel lines converge to vanishing points, mimicking how the eye sees depth.

A method of drawing objects using parallel lines of sight perpendicular to the picture plane, producing true-shape front, top, and side views without perspective distortion.

A pictorial drawing in which the three principal axes are equally inclined at 120 degrees to each other, showing three faces at true scale without vanishing points.