UPMSP Intermediate Physics - Code 151 flashcards

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

Coulomb's law

The electrostatic force between two point charges is proportional to the product of the charges and inversely proportional to the square of their separation, acting along the line joining them.

Gauss's law

The total electric flux through any closed surface equals the enclosed charge divided by the permittivity of free space, regardless of the surface shape.

Capacitance of parallel plates

For a parallel-plate capacitor, capacitance equals permittivity times plate area divided by plate separation; inserting a dielectric of constant K multiplies it by K.

Drift velocity

The small average velocity with which free electrons move opposite the applied field in a conductor; current equals carrier density times charge times area times drift velocity.

Kirchhoff's junction rule

At any junction in a circuit, the sum of currents entering equals the sum leaving, expressing conservation of electric charge in the steady state.

Wheatstone bridge balance

A four-resistance bridge is balanced when the ratio of the two arms on one side equals that on the other; then no current flows through the galvanometer.

Biot–Savart law

The magnetic field due to a small current element is proportional to current times element length times sine of the angle, divided by the square of distance.

Magnetic Lorentz force

A charge moving in a magnetic field experiences a force perpendicular to both its velocity and the field, so the force does no work on the charge.

Cyclotron period

The time for a charged particle to complete one circular orbit in a uniform magnetic field depends only on mass, charge and field, not on speed or radius.

Lenz's law

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

Self-inductance energy

A coil carrying current stores magnetic energy equal to half the inductance times the square of the current, released when the current falls.

Series RLC resonance

In a series RLC circuit, current is maximum and impedance equals resistance alone when inductive and capacitive reactances are equal at the resonant frequency.

Displacement current

A changing electric flux acts like a current in producing a magnetic field; Maxwell introduced it to make Ampere's law consistent for charging capacitors.

Lens maker's formula

The focal length of a thin lens depends on its refractive index relative to the surroundings and on the radii of curvature of its two surfaces.

Critical angle

For light travelling from a denser to a rarer medium, the angle of incidence beyond which total internal reflection occurs, with sine equal to reciprocal of refractive index.

YDSE fringe width

In Young's double-slit experiment, the spacing between successive bright or dark fringes equals wavelength times screen distance divided by slit separation.

Photoelectric threshold

The minimum frequency of incident light below which no photoelectrons are emitted from a given metal surface, equal to work function divided by Planck's constant.

de Broglie wavelength

Every moving particle has an associated wavelength equal to Planck's constant divided by its momentum, observable for electrons and other microscopic particles.

Stopping potential

The reverse potential difference that just prevents the fastest photoelectrons from reaching the anode, measuring their maximum kinetic energy in electron-volts.

Bohr radius

The radius of the first allowed electron orbit in hydrogen, about 0.53 ångström, scaling as the square of the orbit number divided by atomic number.

Half-life

The time in which half the nuclei in a radioactive sample decay; it equals the natural logarithm of two divided by the decay constant.

Mass defect

The difference between the total mass of a nucleus's constituent nucleons and the actual nuclear mass, appearing as binding energy through mass–energy equivalence.

Depletion region

The region near a p–n junction depleted of mobile carriers by diffusion, leaving fixed ions that create a barrier potential opposing further diffusion.

Zener diode regulation

A heavily doped diode operated in reverse breakdown, where voltage stays nearly constant despite current changes, making it useful as a voltage regulator.

Transistor current gain beta

In a transistor, beta is the ratio of collector current to base current; it relates to alpha, the ratio of collector to emitter current.

Vernier least count

The smallest length a vernier calliper can measure, equal to one main scale division divided by the number of vernier scale divisions.

Metre bridge formula

The unknown resistance equals the known resistance multiplied by the balancing length divided by one hundred minus that length, measured in centimetres.

Potentiometer principle

A potentiometer compares EMFs because the potential drop along a uniform wire is proportional to its length when a steady current flows through it.

UPMSP practical marks

In the Intermediate Physics scheme, practical work carries a separate allotment of marks, assessed through a recorded file, viva and an experiment performed in the laboratory.

Chain rule

The derivative of a composite function equals the derivative of the outer function evaluated at the inner function, multiplied by the derivative of the inner function.

Dimensional formula

An expression showing which base quantities and powers make up a derived physical quantity, used to check equations and convert between unit systems.

AM modulation index

The ratio of message amplitude to carrier amplitude in amplitude modulation; it must stay below one to avoid distortion of the transmitted signal.