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Physics > Help x > Flashcards

Help x Flashcards

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Physics 101 flashcards AP® Physics flashcards
1
Q

What is meant by the term refraction?

A

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

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2
Q

What is AC current?

A

current changes direction - continuously

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3
Q

What is meant by the term non-renewable?

A

energy source which cannot be replaced

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4
Q

What colour is a good emitter of thermal energy?

A

black

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5
Q

How does an earth wire act as a safety feature?

A

-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

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6
Q

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

A

metal case conducts electricity - prevent user from getting a shock

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7
Q

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

A

centripetal force

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8
Q

Orbits of moons and planets are slightly…

A

elliptical

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9
Q

Comets orbit…

A

the sun

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10
Q

Satellites orbit…

A

planets

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11
Q

When is an orbit at it’s fastest?

A

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

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12
Q

What is the particle structure of a SOLID?

A

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

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13
Q

What is the particle structure of a LIQUID?

A

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

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14
Q

What is the particle structure of a GAS?

A

random arrangement - move freely in random directions at high speeds

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15
Q

What is the definition of current?

A

rate of flow of charge

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16
Q

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

A

electrons are colliding in the lattice letting off energy

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17
Q

What are the characteristics of EM waves?

A

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

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18
Q

What are the characteristics of sound waves?

A

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

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19
Q

How can we experiment with refraction?

A

-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

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20
Q

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

A

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

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21
Q

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

A

REFRACTIVE INDEX (n)

22
Q

What is the refractive index?

A

describes how light propagates through that medium

23
Q

Why does refractive index have no units?

A

it’s just a ratio

24
Q

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

A

iron filings - sprinkle + tap paper

25
Q

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

A

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

26
Q

When is a uniform field formed?

A

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

27
Q

What is Hooke’s law?

A

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

28
Q

What is the definition of frequency?

A

how many complete waves per second that pass a certain point

29
Q

What is the definition of wavelength?

A

distance from one peak to the next

30
Q

What is the definition of amplitude?

A

height of the wave - from rest to crest

31
Q

How does a gold leaf electroscope work?

A

-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)

32
Q

What if the gold leaves do not rise?

A

rod is not charged

33
Q

Why are metals good conductors?

A

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

34
Q

Why are solids good conductors?

A

particles are close together - strong forces between them

35
Q

Why are materials like wood and plastic poor conductors?

A

no free electrons

36
Q

Why are liquids and gases not conductors?

A

particles are further apart - particle collisions are more difficult

37
Q

How is a convection current set up?

A

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

38
Q

Convection only occurs in…

A

fluids (liquids and gases)

39
Q

Why does convection only occur in fluids?

A

no restrictions to particle movement

40
Q

What hinders convection?

A

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

41
Q

Radiation is the transfer of heat by…

A

electromagnetic radiation

42
Q

What helps radiation?

A

matt black objects, high SA, hotter objects

43
Q

What hinders radiation?

A

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

44
Q

What are the main ways to generate electricity?

A

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

45
Q

What are the advantages of fossil fuels?

A

-reliable
-releases lots of energy
-cheap to run

46
Q

What are the disadvantages of fossil fuels?

A

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

47
Q

What are the disadvantages of nuclear?

A

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

48
Q

What are the advantages of renewables?

A

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

49
Q

What are the disadvantages of renewables?

A

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

50
Q

What is the law of reflection?

A

angle of incidence = angle of reflection

Physics (10 decks)

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