2481048
Description
Flashcards by scouseloewe, updated more than 1 year ago
|
Created by scouseloewe
almost 11 years ago
|
|
| Question | Answer |
| what are the units of frequency, amplitude and wavelength? | wavelengths are measured in metres amplitude is measured in metres frequency is measured in HZ (hertz) |
| the wave equation? | V(=F(HZ)*lambnda (M) |
| electromagnetic waves? | radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma rays |
| effiiciency question? a hairdryer takes in 800 j of electrical energy it gives out 100j of kinetic energy, 300j of heat energy and 400j of sound what's its efficiency? | useful energy out/useful energy in*100 400/800*100 =50% efficient |
| types of energy | kinetic, elastic potential, electrical, magnetic, thermal, nuclear, gravitational potential and chemical |
| specific heat capacity formula and question? the specific heat capacity of water is 4200J/KgoC. how much heat energy does it take to heat up 5kg of water by 40 degrees. | =5*4200*40 =840000J |
| digital communications? | low frequency,high frequency, MF, microwave, UHF and VHF |
| what are optical fibres? | glass wires which help light travel faster |
| heating and insulating buildings | -u-values are measured how effective a material is - |
| the national grid | in the UK electricity is distributed along a power line that travels the country to each and every home. step-up and step-down transformers control the electricity flowing through. |
| conduction | -metals are good conductors of electricity -gases are usually poor conductors of heat, poor conductors are called insulators. |
| convection | -convection occurs when particles with a lot of heat ad energy move -heat energy is transferred from hot places to cooler places by convection. |
| radiation | All objects give out and take in thermal radiation, which is also called infrared radiation. The hotter an object is, the more infrared radiation it emits. |
| cost of electricity formula and question? use a 2kW oven is used for 3 hours 1.how many kilowatt hours of electricity does it use? 2. 1 kWh cost 12p, how much does it cost to use a oven for this time. | answers 1. 2*3=6kW 2. 6*12=72p |
Want to create your own Flashcards for free with GoConqr? Learn more.