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Question 1

What is meant by the term refraction?

Answer 1

change of direction of a wave as it changes from 1 medium to another

Question 2

What is AC current?

Answer 2

current changes direction - continuously

Question 3

What is meant by the term non-renewable?

Answer 3

energy source which cannot be replaced

Question 4

What colour is a good emitter of thermal energy?

Answer 4

black

Question 5

How does an earth wire act as a safety feature?

Answer 5

-earth connected to metal casing
-if casing becomes live/ live wire touches
case, provides low resistance path (to earth)
-large/surge current in earth wire, fuse breaks/melts/blows
-circuit switches/ current supply stops

Question 6

Why should components with metal casing be fitted with earth wires?

Answer 6

metal case conducts electricity - prevent user from getting a shock

Question 7

What force is required for circular motion to occur (orbits)?

Answer 7

centripetal force

Question 8

Orbits of moons and planets are slightly…

Answer 8

elliptical

Question 9

Comets orbit…

Answer 9

the sun

Question 10

Satellites orbit…

Answer 10

planets

Question 11

When is an orbit at it’s fastest?

Answer 11

closest point to object you are orbiting - strong force, so high speed required to remain in orbit

Question 12

What is the particle structure of a SOLID?

Answer 12

particles in a fixed, regular arrangement - particles have less energy so vibrate in fixed positions

Question 13

What is the particle structure of a LIQUID?

Answer 13

particles are close together, slip over each other in irregular/ random arrangements - move in random directions at low speed

Question 14

What is the particle structure of a GAS?

Answer 14

random arrangement - move freely in random directions at high speeds

Question 15

What is the definition of current?

Answer 15

rate of flow of charge

Question 16

Why does current moving in a wire cause it to heat up?

Answer 16

electrons are colliding in the lattice letting off energy

Question 17

What are the characteristics of EM waves?

Answer 17

-transverse
-speed of 3x10^8m/s
-transfer energy but not matter
-travel through a vacuum

Question 18

What are the characteristics of sound waves?

Answer 18

-lontitudinal
-can’t travel through a vacuum
-need particles to propagate
-speed of 340m/s
-transfers information but not matter

Question 19

How can we experiment with refraction?

Answer 19

-set up a ray box with a single beam
-draw around a glass block on a piece of paper
-shine ray of light at an angle into glass box
-draw crosses through the beam as it enters + leaves the box
-add normal line
-remove block and join up the lines
-use a protractor to measure i and r

Question 20

What do you do with your results from a refraction investigation?

Answer 20

find sin(i) and sin(r) - plot a graph (sin(r) on x axis, i on y)

Question 21

What does the gradient of a sin(i) and sin(r) graph tell us?

Answer 21

REFRACTIVE INDEX (n)

Question 22

What is the refractive index?

Answer 22

describes how light propagates through that medium

Question 23

Why does refractive index have no units?

Answer 23

it’s just a ratio

Question 24

How can you find out the shape of a magnetic field?

Answer 24

iron filings - sprinkle + tap paper

Question 25

how can you find out the shape + direction of a magnetic field?

Answer 25

compass - start at north + draw dots in arrow direction, until you reach south

Question 26

When is a uniform field formed?

Answer 26

placing north + south poles of two permanent magnets near each other

Question 27

What is Hooke's law?

Answer 27

the force required to stretch an elastic object is directly proportional to the extension of the object

Question 28

What is the definition of frequency?

Answer 28

how many complete waves per second that pass a certain point

Question 29

What is the definition of wavelength?

Answer 29

distance from one peak to the next

Question 30

What is the definition of amplitude?

Answer 30

height of the wave - from rest to crest

Question 31

How does a gold leaf electroscope work?

Answer 31

-when a charged rod is brought near to the disc of the electroscope, it either repels or attracts electrons -this induces a charge in the metal disc + the gold leaf -the gold leaves will have the same charge + repel each other (causing them to rise)

Question 32

What if the gold leaves do not rise?

Answer 32

rod is not charged

Question 33

Why are metals good conductors?

Answer 33

free electrons which helps particles vibrate and pass energy to adjacent particles

Question 34

Why are solids good conductors?

Answer 34

particles are close together - strong forces between them

Question 35

Why are materials like wood and plastic poor conductors?

Answer 35

no free electrons

Question 36

Why are liquids and gases not conductors?

Answer 36

particles are further apart - particle collisions are more difficult

Question 37

How is a convection current set up?

Answer 37

particles vibrate as heated, spread out and become LESS DENSE - so air rises and falls as it moves further from heat source

Question 38

Convection only occurs in...

Answer 38

fluids (liquids and gases)

Question 39

Why does convection only occur in fluids?

Answer 39

no restrictions to particle movement

Question 40

What hinders convection?

Answer 40

vacuum - no particles, adding a lid, adding foam - air is restricted in foam pockets

Question 41

Radiation is the transfer of heat by...

Answer 41

electromagnetic radiation

Question 42

What helps radiation?

Answer 42

matt black objects, high SA, hotter objects

Question 43

What hinders radiation?

Answer 43

shiny silvery surfaces - stops heat loss by radiation, reflects heat back in, low SA

Question 44

What are the main ways to generate electricity?

Answer 44

fossil fuels, nuclear, wind, wave, tidal, geothermal, hydroelectric, solar

Question 45

What are the advantages of fossil fuels?

Answer 45

-reliable -releases lots of energy -cheap to run

Question 46

What are the disadvantages of fossil fuels?

Answer 46

-produces CO2 (greenhouse gas) -produces sulphur dioxide + nitrous oxides (acid rain)

Question 47

What are the disadvantages of nuclear?

Answer 47

-radioactive waste -meltdown would have a catastrophic effect on environment

Question 48

What are the advantages of renewables?

Answer 48

-cheap to run (no fuel) -does not produce CO2 -does not produce sulphur dioxide or nitrous oxides -supply job in construction

Question 49

What are the disadvantages of renewables?

Answer 49

-initially expensive -unreliable (most weather dependent) -can interfere with wildlife q

Question 50

What is the law of reflection?

Answer 50

angle of incidence = angle of reflection