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Description
Flashcards by sophiewalkerrock, updated more than 1 year ago
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Created by sophiewalkerrock
almost 11 years ago
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| Question | Answer |
| Absorption Line Spectrum | A dark line of a unique wavelength seen in a continuous spectrum. |
| Ampere | The SI unit of electrical current |
| Amplitude | The maximum displacement of a particle from its equilibrium position. |
| Antinode | A point on a stationary wave with maximum amplitude. |
| Charge Carrier | Any charged particles, such as electrons, responsible for a current. |
| Coherent | Two sources are coherent when they emit waves with a constant phase difference. |
| Compression | A region in a sound wave where the air pressure is greater than its mean value. |
| Constructive Interference | When two waves reinforce to give increased amplitude. |
| Coulomb | The SI unit of electrical charge. A charge of 1C passes a point when a current of 1A flows for 1s. 1C=1A's |
| Destructive Interference | When two waves cancel to give a reduced amplitude. |
| Diffraction | The spreading of a wave when it passes through a gap or past the edge of an object. |
| Dispersion | The splitting of light into its different wavelengths. |
| Einstein Relation | This refers to the equation for the energy of a photon- that is: E=hf or E= |
| Electrical Resistance | The ratio of potential difference to current. Unit: ohm |
| Electrolyte | An electrically conducting solution. The conduction is due to positive and negative ions in the solution. |
| Electromagnetic Spectrum | A family of waves that travel through a vacuum at the speed of 3.0 x 10^8 ms-1 |
| Electromotive Force (e.m.f.) | The energy gained per unit charge by charges passing through a supply. Unit: JC-1 or volt (V). |
| Electronvolt | The energy gained by an electron travelling through a p.d. of 1 volt. 1eV=1.6x10-19 J |
| Elementary Charge | The smallest unit of charge that a particle or an object can have. It has a magnitude of 1.6 x 10-19C |
| Emission Line Spectrum | A sharp and bright line of a unique wavelength seen in a spectrum. |
| Energy Level | The quantised energy states of an electron in an atom. |
| Frequency | The number of oscillations of a particle per unit time. Unit: Hertz (Hz) |
| Fundamental Frequency | The lowest frequency stationary wave for a particular system. |
| Ground State | The lowest energy state that can be occupied by an electron in an atom. |
| Intensity | The power transmitted normally through a surface per unit area: Intensity= power/cross sectional area. Unit: Wm-2 |
| Interference | The formation of points of cancellation and reinforcement where two coherent waves pass through each other. |
| Internal Resistance | The resistance of an e.m.f. source. The internal resistance of a battery is due to its chemicals. |
| I-V characteristics | A graph of current against voltage for a particular component. You can identify a component from its I-V graph. |
| Kirchhoff's First Law | The sum of the currents entering any point (or junction) in a circuit is equal to the sum of the currents leaving that same point. This law conveys the conservation of charge. |
| Kirchhoff's Second Law | The sum of the e.m.f.'s round a loop in a circuit is equal to the sum of the p.d.'s in that same loop. |
| Light-emitting Diode (LED) | A semiconductor component that emits light when it conducts. |
| Longitudinal Wave | A wave in which particles oscillate along the direction in which the wave travels. |
| Lost Volts | The difference between the e.m.f. and the terminal p.d. It is also equal to the voltage across the internal resistance. |
| Magnetic Field | A force field created by magnets and moving charges. |
| Mean Drift Velocity | The average speed of charged particles along the length of a conductor. |
| Node | A point on a stationary wave with zero amplitude. |
| Number Density | The number of charged particles per unit volume. Unit: m-3 |
| Ohm's Law | The current in a metallic conductor is directly proportional to the potential difference across its ends, provided its temperature remains constant. |
| Parallel | A term used when components are connected across each other in a circuit. |
| Path Difference | The difference in the distances travelled by two waves from coherent sources at a particular point. |
| Period | The time taken for one complete oscillation of a particle. Unit: Seconds (s) |
| Phase difference | The fraction of a cycle between the oscillations of two particles, expressed in degrees. |
| Photon | A quantum of electromagnetic energy. |
| Plane Polarised | Describes transverse waves that oscillate in only one plane. |
| Potential Difference (p.d.) | The energy lost per unit charge by charges passing through a component. Unit: JC-1 or volt (V). |
| Potential Divider | A circuit in which two or components are connected in series to a supply. The output voltage from the circuit is taken across one of the components. |
| Principle of Superposition | When two or more waves meet at a point, the resultant displacement is the sum of the displacements of the individual waves. |
| Progressive Wave | A wave that carries energy from one place to another. |
| Rarefaction | A region in a sound wave where the air pressure is less than its mean value. |
| Reflection | The bouncing back of a wave from a surface. |
| Refraction | The change in direction of a wave as it crosses an interface between two materials when its speed changes. |
| Resistivity | The property of a material defined by: resistivity=(resistance x cross-sectional area)/ Length Unit: Ohm meter |
| Resistor | An electrical component whose resistance in a circuit remains constant. Its resistance is independent of current or potential difference. |
| Resultant | Total or net |
| Semiconductor Diode | An electrical component made from a semiconductor material (e.g. silicon) that only conducts in one direction. A diode in 'reverse bias' has an infinite resistance. |
| Series | A term used when components are connected end-to-end in a circuit. |
| Stationary Wave | A wave pattern produced when two progressive waves of the same frequency travelling in opposite directions combine. It is characterised by nodes and antinodes. Also known as a standing wave. |
| Terminal p.d. | The potential difference across the external resistor connected to an e.m.f. source. |
| Threshold Frequency | The minimum frequency of the electromagnetic radiation that will eject electrons from the surface of a metal. |
| Transition | When an electron makes a 'jump' between two energy levels. |
| Transverse Wave | A wave in which the oscillation is at right angles to the direction in which the wave travels. |
| Wave | A periodic disturbance travelling through space, characterised by vibrating particles. |
| Wavelength | The distance between two adjacent peaks or troughs. |
| Work Function | The minimum energy required by a single electron to escape the metal surface. |
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