Assam Higher Secondary Physics flashcards

34 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 joining line.

Electric dipole moment

A vector of magnitude q times the separation between equal and opposite charges, directed from the negative to the positive charge. It determines torque and field of the dipole.

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.

Drift velocity

The small average velocity with which free electrons move opposite to the applied electric field in a conductor, typically of order 10⁻⁴ metres per second.

Wheatstone bridge balance

A four-resistance bridge is balanced, with no galvanometer current, when the ratio of the two arms on one side equals the corresponding ratio on the other.

Kirchhoff's junction rule

The algebraic sum of currents entering any junction of a circuit is zero, expressing conservation of electric charge at that point.

Biot–Savart law

The magnetic field due to a small current element is proportional to current and element length, and inversely proportional to the square of the distance, with a sine dependence on angle.

Ampere's circuital law

The line integral of magnetic field around a closed loop equals the permeability of free space times the net current passing through the loop.

Current sensitivity of galvanometer

The deflection produced per unit current, equal to NAB/k for a moving-coil galvanometer, where k is the torsional constant of the suspension.

Lenz's law

The induced current flows in a direction that opposes the change in magnetic flux producing it, a consequence of conservation of energy.

Self-inductance

The property of a coil by which it opposes any change in current through it, producing a back emf proportional to the rate of change of current.

Resonant frequency of LCR

The frequency at which inductive and capacitive reactances are equal, giving minimum impedance equal to resistance and maximum current in a series circuit.

Displacement current

A fictitious current proportional to the rate of change of electric flux, introduced so that Ampere's law holds between capacitor plates during charging.

Total internal reflection

When light travelling in a denser medium strikes a rarer medium beyond the critical angle, it is entirely reflected back with no refracted ray.

Fringe width

The separation between consecutive bright or dark fringes in Young's double-slit experiment, equal to wavelength times screen distance divided by slit separation.

Stopping potential

The reverse potential difference that just stops the fastest photoelectrons, so that the maximum kinetic energy equals the electronic charge times this potential.

de Broglie wavelength

The wavelength associated with a moving particle, equal to Planck's constant divided by its momentum, showing matter has wave properties.

Work function

The minimum energy needed to remove an electron from the surface of a metal, related to the threshold frequency by Planck's constant.

Bohr radius

The radius of the first allowed electron orbit in hydrogen, about 0.53 angstrom, scaling as the square of the principal quantum number.

Half-life

The time in which half the nuclei in a radioactive sample decay, equal to the natural logarithm of two divided by the decay constant.

Binding energy per nucleon

The total nuclear binding energy divided by mass number; it peaks near iron-56, so energy is released by both fission of heavy and fusion of light nuclei.

Depletion layer

The region around a p-n junction depleted of mobile charge carriers, containing fixed ions and producing a barrier potential that opposes further diffusion.

Zener diode

A heavily doped diode operated in reverse breakdown, where the voltage stays nearly constant over a range of currents, used for voltage regulation.

Transistor current gain beta

In common-emitter configuration, the ratio of collector current to base current; it relates to alpha by beta equals alpha divided by one minus alpha.

Dimensional formula

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

Projectile range

The horizontal distance covered by a projectile returning to its launch height, equal to initial speed squared times sine of twice the angle, divided by g.

Newton's third law

For every force exerted by one body on another, the second body exerts an equal and opposite force on the first, acting on a different body.

Banking angle

The angle to which a road is tilted so that the horizontal component of the normal reaction supplies centripetal force, given by tangent equal to v squared over rg.

Work–energy theorem

The net work done by all forces on a body equals the change in its kinetic energy, valid even when non-conservative forces act.

Rolling without slipping

Motion in which the contact point has zero velocity, linking linear and angular speeds by v equals omega times radius, with both translational and rotational kinetic energy.

Escape speed

The minimum launch speed for a body to escape a planet's gravity without further propulsion, equal to root two times the orbital speed at the surface.

Carnot efficiency

The maximum possible efficiency of a heat engine operating between two reservoirs, equal to one minus the sink temperature divided by the source temperature in kelvin.

Simple pendulum period

The time for one complete oscillation of a small-angle pendulum, equal to two pi times the square root of length divided by gravitational acceleration.

Doppler effect

The change in observed frequency of a wave due to relative motion between source and observer, rising on approach and falling on recession.