EXAM Flashcards by Pua Sar

Explain 1 disadvantage caused by solar cells only facing one direction.

Solar cells don’t track the sun and won’t generate as much electricity.

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When ball hit ground, energy is transferred from ball to earht. Explain the energy transfer.

Velocity after bounce is decreased, with the loss of kinetic energy. Means the ball has lost its energy as height from top of bounce is less than height dropped.

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nuclear fusion is the joining together of …..
during nuclear fusion the totoal mass of the particles….

nuclei, decrease

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Why were modeles tested befre starting to build?

To devlop understanding of process and to assess safety risk.

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Explain 1 environmental effetc of genertaing electricity using fossil fuel

realses carbon dioxide which causes global warming.

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Explain the effect of 2 other factors on braking distance of car. ( no speed include)

Braking distance of car can be effected due to, poor road surface as wet or icy road, amking the poor condiiton on tyres to be worn brakes. This is because decreased fricitin as it slows tyres to brake.

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When rider reach bottom of slide, sled decerlates and stop. Give 2 factors that affect how far the sled will move before it stops.

Speed at bottom of slide and fricition between sled and ground.

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LED lamps are much more effcient than filament lamp means?

LED lamp waste a smller proportion of input energy than filament lamp.

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Why might filamenet inside a lamp melt when the lamp is first switched on?

The current goes too high.

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Connecting 2 reisotrs in parall circuit, what happen to total resistance of circuit

Decrease because totoal resistance is always less than smallest indiivudal resistance.

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2 envirnemntal issue caused be genertaing electricty using nuclear power ststaion

Waste is radioactive and is toxtic

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why can parallel circuit operate wither 2 swithc

because switch in parallel so closiing either switch completes the circuit.

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why the fricition between sock and carpet make studen charge

transfer of electrons fro the carpet to the student.

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Negative charge student touch a metal tap and recive electric show why

because there is P.D between student and the tap which causes charge to transfer from the stuent.

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expain one envuronemntal problem cause when electrictty is generated by buring coal

release carbon dioxide causes global warming.

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why did studetn insulate beaker of water in specific heat coaicty experinent.

to reduce energy trasfer to the surroduniing

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rider reach bottom of slide, sled declertaes and stop, 2 reason that affect how far the sled will move before it stops.

speed at bottom of slide and friciton between sled and ground.

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the cells were put into torch the wrong way round, why the troch didnt work

there is no current in diode inthe revser direcetion because has very high resistance in reverse direction

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describe use equipment on syringe and pressure gauge to obtain data

record intial volume of air
record the intial pressure
push the plunger of syringe to decrease volume of air
read nd record new wavlue of pressure guage and volume
rpet for different vlumes

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describe method student on investigate how quickly kettle could increase the tempt of water

measure mass of water use balance
measure inital tempt of water use thermoter
pour water into kettle
place thermoter in water]
switch kettle on
take recording of tempt of water every 5secon
record with stopclosk

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for safety, it is important that the bungee cord used is appropiate for students weight, why?

bungee rope may snap and extend too much

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Explain what led to the plum pudding model of the atom being replaced by the nuclear model of atom

The alpha particle scattering experiment have led changes as alpha particle directed at gold foil. Most of alpha particles pas staright through so msot of atom is empty space. Plum pudding model has mass spread throughout atom and change spread.

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explain why people should be encouraged to use energy efficent electrical device

more effiecent devices waste less energy which minismise the electricity demand

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some energy from wind used to rotate is wasted. engineer oils mechanical parts wind trubine how does oiling affet efficicency of wind turbine

efficiecny increases because amount of wasted energy would decrease. Lubrication of oil mean less fricition

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what is 696 MW

696 000 000

how will increase resistance of varibale resistor in series affect: - current in circuit - p.d across lamp - total resit

decrease, decrease, increase

which particle in atom was discovered first

electron

what is half-life

time taken for half the nuclei in a sample to decay

what is nuclear fusion fuel and nuclear fission fuel

hydrogen, uranium

student could not make valid conclusion from the result about how different insluating matierla affect the energy transfer. explain 2 ways that student could imporve this

use the same number of layers of insulation so that the tempt difference can be compared. use the same volume of water so the same area of bottle surface is heated by the water.

why use bar chart

is labels/catergories/// is not numerical values

B student move toward river and cord stretchs, how does B compare energy store with A standing still. - less than A or more than A grav potential engerg- kinetic - elastic-

less than at A, more than A, more than A

Bungee A spring const - 78.4 , extens- 36, B= 82, ext-24, C= 84.5, ext-12. Why will C have smaller extension than A

greatest spring constant

particles in gas move with .... move in ...

range of speeds, random direction

volume gas increase, pressure decreases, tempt same. How does increase volume effect: - meantime betwen collosion of particles - mean dstant between particles - mean speed of particles

- increase - increase - same

why student left thermometer in iron block for few mins before record inital tempt

so the thermoter tempt was the same as tempt of iron block

explain change in arrangement and movement of soild and liquid particles as ice melt and tempt increase to 5 degree

particles in soild are in regular pattern and liquid are in random arrangement. Particles in soild are visbrating about dixed postion when heated, and lqiuid are mvoing freely. So, as the ice changes to water the tempt remain constant and potentail energy of particls increase. As the water warms, particles move faster so does the kinetic energy. This increases internal energy of the total kinetic and potentail energy of all the particles.

describe the action of the 5A fuse in a circuit

if currrent is above 5A, the fuse will melt and cause it to break the circuit

Explain functions of live, neural , earth wire

live wire carries p.d of 230v from the main supply. Neutral wire completes the circuit. Earth wire is safety wire to stop casing appliances becoming live

Transformer p.d steps up the 25kV to 400kV. Explain why

Increasing p.d decrease the current. So the smaller current means less energy changed to thermal energy in cabels

Explain how the balloon become negatively charged when rubbed on jumoer and what happens to jumoer

Electrons are transferred from jumoer to balloon. Jumper now positively charged because looses electrons

explain in terms of particles, why gases are easy to compress

large gaps between particles, so easy to push particles close together

fox have large ears, explain how size of ears help it to keep cool in hot desert

fox ears have large surface, this radiates heat/ or(any) keep blood cooler

difference of soild and gas on space, movement and force. info soild - fixed shape, diffuclt to compress(squash) gas - spread, fill entire container, easy to compress(squash)

Soild particles are close together in a fixed position, it is strongly held together. So no room for particles to move hence hard to compress. - Soild vibrates in fixed postion and strong force of attraction. Gas particles are far apart, random directions, and have space between each particle. Hence easy to push particles closer. -Moves randomly have have no force of attraction.

describe characteristic of alpha and beta strcutre, penetrate through air and material, deflection electric field

Alpha - consist of helium nuclues + 2 protons and neutrons. -Absorbed by thin paper +skin -Penetrate a few cm in air. Beta - consist electron from nucleus comes from. -Pass through thin metal plate. -Travel further than alpha particle in air, several metres in air. ALPHA AND BETA deflected in opposite direction in an electric field.

why is it impossible for alpha and beta decay produce same element.

alpha and beta produce different number of atomic number, so number of prtons determine the elemnt.

why does beta decay not change mass number

number of neutrons decrease by 1, number of protons inceease by 1

neutral atom has no overall charge, explain in terms particles. ELCTRON - -1, PROTONS +1 ,NEUTRONS 0

an equal opposite charge because number of protons equal to number of electrons

why people may be concerned about safety of eat irridated foods

people may link the use of radioation with illness

give reason why farmers, consumers, hsop owerners, may want foood to be trated with radiaiton

less likley to not get food poisoning.

one way process of nuclear fusion differs from process of nuclear fission

nuclei are joined not split

describe what happens to nuclues of atom during nuclear fission

splits into 2 smaller parts and 2 nuetron

why person may recive higher than avergae dose of radiation from bakcground source

working at nuclear power stations

Briefly what is difference between nuclear fission and nuclear fusion

nuclear fission split atomic number, nuclear fusion is joining 2 atomic nuclei to form a larger one.

how does fox with small ears survive in cold weather

fox with smaller ears have thicker fur so this minimises energy transfer

why national grid use high voltage with small current to transfer electricuty

smaller current reduces heating effect in cables, so less energy wasted in cables.

describe energy transfer that happen when ball hit wall

kinetic energy transfers to thermal energy

1 safety precaution to take when use electric heater

do not touch heater when switched on

describe 1 ways radioactivity can be used to disagnose cancer, and 1 radioactivity to treat cancer

Tracer is radioactive source. -injected into patient and travel around body. -emits gamma radiation -so can be dected outside of the body with gamma camera Radiotherapy to treat cancer cells by use of X-ray. - x-ray kills cancer.

explain why student should open switch after each reading on resistance experiment

resistor would get hot if current left on, so it increases resistance

householder always fill electrical kettle to top, even when for 1 small cup. how is this wasting money

bigger volume takes more time to boil. so more energy transferred and this costs more money.

why use line graphs and not draw bar chart

data are contineous

as move comb away hair, it attracts the hair what happened to comb

become electrically charged

why is static electricity dangerous and not useful for refuelling aircraft

spark may causes an explosion

rub hands around comb, causes comb to no longer attract hair - why

charge gone to body

describe action and purpose of solar panel seen on roof of house

water heated by radiation from the sun, water used to heat building

explain in particles how heat is transferred through glass wall of boiling tube

kinetic energy of particles increase so particles gain enervy to vibrate

why is dirty surface solar panel not generate much

no gnerate electriicty because less light hitting solar panel

what must be done each time a tree is chopped down and is renewable

plant at least one new tree

advantage of turning off electricity appliances when not being used

less fossil fuel burned

describe changes in movemetn of particlesn as ice cube melts.

Melt - soild to liquid. When in soild form particle vibrate about fixed position. Partilce in liquid move freely and not fixed position.

3 liquid in large measuirng cyclinder have different densities are seperated and sit on top of each other. why

high density will be at bottom(sink) low density will be at top(float).

2 precautions for measuring density of irrgular object

place measuring cyclinder on level surface and read at an eye level.

describe difference between soild and gas in term arrangements and movement

soild particle are regular pattern and vibrate about fixed psotion. Gas partilces moves randomly and far apart.

when a person uses the shower the mirror gets misty why

water evaportes and water particles that hit the mirror loses energy

polythene gloves do not stop hands being irridated, explain why wear

prevents contamination

why is it important to warn people that radiation source is being used

radiation damage cells

why are some atoms radioactive

nuclei unstable

explain why it would be dangerous injgest (swallow) alpha

alpha is highly ionsing and will damage cells

what is hazard of ionsing radiation enetr body

will damage to cells and increase risk of cancer

explain why it is safe to eat fruit that has been irridated with gamma ray

gamma rays will kill bacteria on fruit.

what is meant by the random nature of radioactive decay

impossible to tell which nuclei will decay next, and impossible to tell when nuclie will decay

EXAM Flashcards

(82 cards)