P7.1 Energy Flashcards

Question

Why energy sources change dived time? Problem of energy supply like what happen to renwable prices what governemnt consider when picking renwable also for renwable

Answer 1

Population expand from 1 billion to 7 billion today so more energy More devices using fuels used Non renewable finite and run out , and as basic rule of supply and demand as supply lower deman increase and expense too Burning fossil fuels produce co2 contribute to climate change , leading to more sea level rising and weather pattern and food disruption Govemnemt tryha. Increase renewable as a streust but consider price, effect in environment to set them up (energy used), contribution to climate change and how worth it is it compared to the effect it brings also like geothermal cant bare be used everywhere

Answer 2

230 v with 50 hz = mains DC comes from batteries and the marinas, AC comes when alternating of happens creating ac, but in the national grid

Answer 3

National grid is just grid of wires network from everywhere higher currents means p= i2r somire power is lost, meaning more fuels needed and energy overall- eneegu transferred to surroundings and wires heat up. - wasted energy costs more, much cheaper to step up and thus NATIONAL GRIDE EFFICIENT WAY TO TRASNPORT CURRENT thus step UP used from geberator to grid network so the plwer lost is minimal ans xosn step down to homes, from like 400000 to 230 this is possible using ratios of cables and idea that power= power2 Transformers change the old of wires to reduce the heating effect and therefore MORE EFFICENT way to distribute electricity . When current flows, then heat of wire increase- inefficient as resistance increase too, You transfer a power = vI. High powers must be transferred, so either high I or high V. But high I will increase to high temp and is inefficient . Power dissipated = I2 R that’s why. - so transformer used to step up / down pd to make it effiecnet.

Answer 4

High current used means more power lost, so more power will need to be generated to accumulate- resulting in more fuels being used er. Therefore high voltage used , then low voltage. Power coil1= power coil 2, where none is lost and temp doesn’t increase VC= V2C2 Remember when an alternating current is inputted into the primary coil, an alternating magnetic current is formed around it, inducing the iron core with an alternating magnetic field. This carries over to the second coil, and an alternating current is induced in the conductor , base don the coils ratio. More in 1 then 2, step down, more in 2 then 1, step up. Assume they are almost 100% efficient

Answer 5

Earth wire = green and yellow Live wire= BROWN Natural wire = blue Live to neutral and earth = 230 Neutral to earth = 0 1) life carries to voltage alternating between - and positive 230. Neutral completes the circuit, out of the wire so 0v. Earth for safety If live wire becomes loose inside and touches metal casing the casing would become live and is now dangerous, as body is 9v so pd is huge snd current will be big killing you Therefore earth wire connected to casing so if that happens, current will go to earth wire, and this resistance is low increasing current because v=is, and this melts the fuse. Breaking the circuit, prevent harm. Earth goes to ground connecting circuit there If it has non conductive casing like plastic don’t need earth wire, as it has casing and non conductive like plastic it’s double insulated

Answer 6

Energy is the ability of an object to do work When word is done by an object , energy transfers from the object to something When work is done by the object energy is transferred to the object

Answer 7

Mechanically, due to a force acting on it Electrically with an electric current Heating with particles where energy go from hot to cold Heating by radiation , energy transferred by light or sound waves so like sun.

Answer 8

Walls floor roof and window Low so igloos can be warm

Answer 9

Conduction happens in solids - hot object has higher kinetic - this vibrates and collided with other particles adjacent, making them vibrate too. Increase their temp and this happens until temp across object is same Convection happens in gas and liquid - idea that particles with more kinetic energy move from hotter to cooler region and take kinetic energy with them - this means cool air takes its place and circulation of convection currents occur heating evenly - reduce convection stop movement of air, so like clothes traps air pockets , and so energy conducts slowly and you warm . 3) radiation is where energy is transferred via em wave of infra red which don’t need particles - hot objects emit more infra cold emit less - cooler object absorb this infra and temp increase - black absorb more white less

Answer 10

Loft insulation of FIBREGLASS WOOL - hot water tank - double glazing reduces conduction - thick curtains - cavity wall insulation- where gaps between wall stops conduction and insulation foam stops convection THICKER WALLS AND LOWER THERMAL CONDUCTIVITY - pipes insulate paint white etc

Answer 11

P=e/t GPE= m X G X H Elastic?= 1/2 spring constant X extension ^2 Kinetic =1/2 mv^2 force = m xa

Answer 12

because used exagerated reaction time

Answer 13

force = m x a a revilves time , increase time reduce a and reduce force the time is collision time. to increase this, you need CRUMPLE ZONES AIR BAGS SEATBELTS TOO, which all deform rsther thsn shatter allowing collison time ti increase. finally motorway railings also have. the max speed motorway should be 70

P7.1 Energy Flashcards

(37 cards)