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Physics (Unit 1)
revision for mid year exam
Term | Definition |
---|---|
Wave | > transmission of energy through periodic oscillations, w/o a net transfer of matter. |
Mechanical Wave | > waves or oscillation of physical matter. eg. water, seismic, sound waves |
Electromagnetic Wave | > oscillations of the electromagnetic and magnetic fields, commonly referred to as light. |
Transeverse Wave | > perpendicular to the direction of the wave propagation. eg. electromagnetic waves, water waves |
Longitudinal Wave | > parallel to the direction of wave propagation. eg. sound waves, P waves in earthquake. |
Properties of wave | > amplitude, wavelength, period, frequency. |
Electromagnetic radiation | > the sun emits electromagnetic radiation across a wide range of frequencies. |
Electromagnetic spectrum | > when a charge accelerates, changes velocity, it produces electromagnetic radiation. |
Black body | > an object that radiates energy but does not reflect it. eg. the SUN. |
Diffraction | > spreading out of a wave due to passing through a gap or around an object. |
Dispersion of white light | > The seperation of light into component colours due to refraction (different frequencies refract by different amounts.) |
Mirages | > light refrcts & totally internall reflects to create mirages. - light move fast = hotter air - light move slow = cold air |
Optical fibres | > utilise total internal reflection to make use of light for communication. - inner cladding has a higher refractive index compared to the outer cladding in order for total internal reflection. |
Refraction | > a change in direction of a wave at a boundary due to a change in speed. |
Refractive index | > a measure of the relative speed of light through a medium compared to a vaccuum. - greater refractive index = slower light will travel. |
Snell's Law | > mathematical relationship between the angle of the incident and refractive ray when measured to the normal. n1 sin(θ1) = n2 sin(θ2) and n1v1 = n2v2 |
Total internal reflection | > occurs when the angle of incidence predicts a refracted angle greater than 90 degrees. |
Critical angle | > the angle of incidence at which the refracted angle is 90° - beyond this angle, total internal reflection occurs. |
Temperature | > the measure of averaget translational kinetic energy of particles within a substance. |
Heat | > transfer of thermal energy. |
Conduction | > transfer of heat through collision. |
Convection | > transfer of heat through mixing of fluids. |
Radiation | > transfer of heat due to emission and absorption of electromagnetic radiation. |
Specific Heat Capacity | > the amount of energy (Joules), you need to heat up 1 kilogram of a substance by 1 degree. - change in temp. |
Latent heat | > energy required to change the state of 1 kg of a material without a change in temperature. - change in phase. |
Kelvin and Celsius | > Kelvin = Celsius + 273.15 > Celsius = Kelvin - 273.15 |
Wien's Law | > temperature of a black body increases = the wavelength of greatest emitted intensity decreases. - hotter star = peak wavelength decreases = frequency increases = colour change |
Effect of temperature on emitted energy | > hotter objects emit more radiation at all wavelengths BUT proportions differ. - higher frequency radiation = more energetic. |
Half life | > the time it takes for half of a radioactive sample to decay. |
Alpha decay | > unstable nucleus decays into a more stable nucleus by emitting an alpha particle (basically just a helium atom). |
Beta minus decay | > unstable nucleus decays into a more stable nucleus by transforming a neutron into a proton and an antineutrino. |
Beta plus decay | > unstable nucleus decays into a more stable nucleus by transforming a proton into a neutron and emitting a positron and a neutrino. |
Gamma decay | > process by which an excited nucleus decays into a more stable nucleus by emitting energy in the form of gamma rays. |
Conservation of mass/energy in Nuclear Physics | > anything with mass has an inherent energy proportional to its mass. this relationship reveals that there is a tremendous amount of energy contained in small amounts of mass. this also means that when energy is added, its mass increases. - E = mc^2 |
Mass defect | > the difference in mass between a nucleus and its constituent nucleons. |
Fusion | > forcing several smaller nuclei together to form a single larger nucleus. - the reactant nucleus must be forced together where the strong force overcomes the electrostatic forces, very high temps, immense pressure. |
Fission | > splitting a single nucleus into several smaller nuclei. |
Quark | |
Nucleons | |
Strong force | |
Weak force | |
Absorbed dose | |
Effective dose | |
Equivalent dose | |
Ionising impact | |
Tissue weighting factor | |
Binding energy | |
Control rod | |
Neutron moderators | |
Neutron multiplication factor | |
Criticality | |
Subcriticality | |
Supercriticality | |
Fissile | |
Voltage | |
Current | |
Resistance | |
Charge | |
Electric PotentialEnergy | |
Ohm's Law | |
Voltage divide | |
Diode | |
LED (light emitting diode) | |
Potentiometer | |
Transducer | |
Thermistor | |
LDR (light dependent resistor) | |
Variable resistor | |
Ohmic devices | |
Non-ohmic devices | |
Power(formulas) | |
Watt | |
kW (kilo Watt) | |
kWh (kilo Watt hour) | |
Direct Current (DC) | |
Alternating Current (AC) | |
Fuses | |
Circuit Breakers | |
Residual current devices (RCD) | |
Earth wire |