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Physics > Physics > Flashcards

Physics Flashcards

1
Q

What’s a permanent magnet

A

A permanent magnet is a material that is constantly magnetised and cannot be turned in or off

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2
Q

How does a electromagnet work

A

An electric current is wrapped around a metal in coils this current males the atoms in the metal all face the same way meaning a magnetic field occurs it can be turned on or off

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3
Q

What’s an electromagnet

A

A electromagnet is a material that can be magnetised through a current that can be switched in or off

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4
Q

What’s the earths magnetic field

A

The earth has a magnetic field very similar to a bar magnet. This field runs from the north to the south poles of the earth

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5
Q

What’s a solenoid

A

A solenoid is a metal with with a current coiled around it

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6
Q

What’s Flemings left hand rule

A

Thumb for movement
First finger the field (magnetic)
Second finger current

LEFT HAND

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7
Q

Right hand thumb rule

A

Point your hand up in thumbs up style and the curls of your fingers show the direction of the magnetic field

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8
Q

How does a motor work

A

A motor works by a coil of wire with a current running through it causing it to turn in a circle

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9
Q

How does a generator work

A

A generator works by putting electrons through a wire from mechanical movement, the electrons are then pushed down the wire at a steady rate producing electricity

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10
Q

What does a step up transformer do

A

It increases the voltage

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11
Q

What’s a step down transformer

A

Decreases the voltage

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12
Q

What’s the voltage at on the main lines

A

400000

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13
Q

Why do they increase the voltage in the main lines

A

Because as you increase current you decrease the resistance meaning less energy will be used up as thermal

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14
Q

What is the voltage when it comes out of the socket

A

230

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15
Q

What’s the voltage when it come from the power station

A

25-35000

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16
Q

Voltage

A

The difference in the energy carried by electrons before and after a component ( potential difference)

= current times resistance

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17
Q

Current

A

Flow of electrons through circuit

Charge / time

Electrical power / potential difference

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18
Q

Coulombs

A

Unit of electrical charge

1 Coulombs = charge that passes a point in a circuit when there is a current of 1 amp for 1 second

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19
Q

LDR

A

Light Dependant Resistor

Resistor where resistance decreases was light intensity increases

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20
Q

Resistance

A

How hard it is for electrons to flow through something

Current x voltage

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21
Q

Electrical Power

A

Amount of energy transferred every second (W)

= current x potential difference

= current* x resistance

= energy transferred / time taken

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22
Q

Series circuit

A

When there’s one loop of circuit and the electricity flows through everything on one loop

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23
Q

Parallel circuit

A

When there are multiple loops of circuits that are parallel to each other

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24
Q

What is background radiation

A

Natural forms and substances of radioactive material

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25
Q

Sources of background radiation

A 
Medical
Ground / buildings
Cosmic rays
Food and drink
Nuclear
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26
Q

When is a nucleus radioactive

A

When the nucleus is unstable

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27
Q

What is alpha decay

A

When the nucleus emits a helium nuclei of 2 protons and 2 neutrons

28
Q

What happens in beta - decay

A

Neutron turns into a proton and electron, the electron is emitted

Atomic number increases by one

29
Q

What happens in beta + decay

A

Proton changes into a neutron and electron

Atomic number goes down by one

30
Q

What’s the half life

A

Time taken for half an unstable radioactive nuclei to decay

31
Q

Nuclear fission

A

Large nuclei break up to form smaller nuclei and release energy

Used in power stations

32
Q

Nuclear fusion

A

Two smaller nuclei join together to form a larger nucleus

Happens in the sun

33
Q

Scaler

A

Size or magnitude but no direction

Energy
Mass
Distance
Speed
Temp
34
Q

Vector

A

Size or magnitude and a specific direction

Force weight 
Velocity 
Acceleration
Momentum
Displacement
35
Q

Newton’s first law

A

An object will remain at rest or continue in a straight line at a constant speed as long as the forces acting in it are balanced

36
Q

Newton’s second law

A

When a resultant force acts on a mass then there will be a change in velocity

37
Q

Newton’s third law

A

Everything has an equal and opposite reaction

38
Q

What happens in circular motion

A

the speed is constant the velocity is changing

The centripetal force is acting inwards to the circular motion

39
Q

Human reaction time

A

Time between the stimulus and the response

40
Q

Stopping distance

A

Total distance over which a Vehicle comes to rest

Affected by baking distance + thinking distance

41
Q

Energy stores

A 
Chemical
Kinetic
Gravitational potential
Elastic potential
Thermal
Magnetic
Electrostatic 
Nuclear
42
Q

Longitudinal waves

A

Sound waves seismic P waves

Particles travel back and forth

43
Q

Transverse waves

A

Electromagnetic and seismic S waves

Moves like waves on water

44
Q

Speculation reflection

A

When light is reflected evenly across a surface

45
Q

Diffuse reflection

A

When light is reflected unevenly due to there being a rough surface

46
Q

How are lenses made more powerful

A

The higher the power of the lens the greater it bends light

47
Q

What’s a converging lens

A

Bends rays of light inwards towards one another

48
Q

Diverging lens

A

Bends rays of light away from each other

49
Q

Nuclear radiation

A

Energy is released from an unstable nuclei

50
Q

Isotope

A

Same number of protons different number of neutrons

51
Q

Ultrasound

A

Waves with a frequency above 20000 Hz

52
Q

Infrasound

A

Waves with a frequency below 20 Hz

53
Q

Doppler affect

A

When light and sound waves wavelength change due to whether the source is moving to the object or away

Wave length is larger when the source is moving away from you

Wavelength is shorter when it’s moving towards you

54
Q

Ohms law

A

Relates to how the current through a component relates to its resistance and the potential difference across it

55
Q

Resistance

A

How hard it is for electricity or electrons to pass through a component

56
Q

Thermistor

A

Resistance decreases as temp increases

57
Q

Ac current

A

Alternating current

Looks like a wave

58
Q

DC current

A

Direct current

Straight line

59
Q

What does a transformer do

A

Change the size of the voltage of an alternating current or voltage

60
Q

Does a transformer increase voltage

A

By putting voltage into wiring on one side of the iron this creates an electromagnetic field. On the other side there are more wires which pick up the electron in the field and due to there being more wiring this means more electrons can pass through increasing the voltage

61
Q

How does a fuse work

A

If the wire gets to hot it will heat to the point where the wire breaks stopping the circuit

62
Q

Negatively charged insulators

A

When negative electrons move onto insulator off the cloth due to friction

63
Q

Positively charged insulators

A

When negatively charged electrons move from insulator to the cloth due to the force of friction

64
Q

Electrostatic induction

A

A charged object can attract a non-charged object, because it induces a charge in the uncharged object

65
Q

Electric field of a positive charge

A

Acts outwards

66
Q

Electric field of a negative charge

A

Acts inwards

Physics (3 decks)

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