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IGCSE Physics (AGR 2018/19) > Main > Flashcards

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1
Q

What are the benefits of using electrostatically charged spray paint?

A

Paint has same charge so repels = fine mist, no clumps. Object has opposite charge, attracts paint into corners and around the back

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2
Q

What are the advantages of wind power?

A

Renewable,no air pollution,low running costs, no fuel costs

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3
Q

What sort of electricity is needed to make transformers work?

A

AC; current must change direction so magnetic field keeps changing direction

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4
Q

Equation: kinetic energy, mass and speed

A

kinetic energy = ½ x mass x speed²

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5
Q

What is another name for the rate of flow of charge?

A

Current

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6
Q

Equation: energy transferred and work done

A

energy transferred = work done

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7
Q

Time

A

second, s

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8
Q

Describe the arrangement and motion of particles in a liquid

A

Irregular pattern;Able to move over/past other particles;Little space between particles;

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9
Q

Equation: pressure, force and area

A

pressure = force ÷ area

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10
Q

Resistance, R

A

ohm (Ω)

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11
Q

Factors which affect braking distance

A

Speed, weight of vehicle, quality of brakes and tryes, road surface

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12
Q

gravitational potential energy, mass, g and height

A

gravitational potential energy = mass x g x height

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13
Q

Give a use for x-rays

A

looking at the insides of things (medical imaging and other objects)

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14
Q

What does work done = energy transferred mean?

A

If you do 10J of work on a system you transfer 10J of energy to it.

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15
Q

What is the frequency range for human hearing

A

20 Hz - 20 000 Hz

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16
Q

What is the role of the moderator in a nuclear reactor?

A

To slow neutrons down so that they can cause new fissions

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17
Q

What particle do control rods absorb?

A

Neutrons

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18
Q

The gradient of a distance-time graph gives

A

Speed

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19
Q

Equation: pressure difference, height, density and g

A

pressure difference = height x density x g

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20
Q

What are the artificial sources of background radiation?

A

Medical sources, fallout from nuclear weapons testing and use, nuclear accidents

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21
Q

Mass, m

A

kilogram (kg)

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22
Q

Velocity

A

metre per second, m/s

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23
Q

If you double the volume of a sealed container of gas (at a constant temperature) what happens to the presure?

A

Pressure will halve

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24
Q

When investigating the relationship between pressure and volume what two quatities must you keep constant?

A

Temperature and mass of gas must be kept constant when investigating pressure and volume

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25
Q

Density, ρ

A

kilogram per metre cubed (kg/m³)

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26
Q

The initial linear part of a force-extension graph is linked to what law?

A

Hooke’s Law (Force is directly proportional to extension)

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27
Q

What is the law of reflection?

A

Angle of incidence = Angle of reflection

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28
Q

How can you prevent heat transfer by radiation?

A

Shiny surfaces are poor emitters. They also refelect the thermal radiation back.

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29
Q

What is the critical angle

A

When ligh hits the boundary at the critical angle the angle of refraction is 90°

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30
Q

Wavelength, λ

A

metre (m)

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31
Q

Comets orbit what? What shapes are their orbits?

A

Comets orbit stars (e.g. the Sun) in elliptical orbits

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32
Q

average speed, distance and time

A

speed = distance ÷ timeaverage speed = total distance ÷ total time

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33
Q

The area under a velocity-time graph gives

A

Distance travelled

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34
Q

Pressure

A

pascal, Panewton per metre², N/m²

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35
Q

How would you find the volume of a regular object (e.g. a cube of metal)

A

measure each side (with ruler) and multiply together

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36
Q

What happens when current flows through a resistor

A

When current flows through a resistor it heats up (this effect is used in kettles and toasters etc.)

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37
Q

When a magnet moves through a coil of wire what happens?

A

A magnet moving through a coil causes a current to flow

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38
Q

How can you increase the amount of voltage which is induced when moving a magnet into a coil?

A

Stronger magnet, move magnet faster

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39
Q

Name some electrical conductors (low resistance, allow current to easily flow)

A

Metal, graphite

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40
Q

When the angle of incidence is greater than the critical angle light is…

A

Totally internally reflected

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41
Q

Describe how thermal energy is transferred by radiation

A

Thermal radiation is an electromagnetic wave.

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42
Q

kilo

A

1 000

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43
Q

Name some vector quantities

A

Velocity,displacement,acceleration,force,momentum,moment,current

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44
Q

Why is a current induced in the secondary coil?

A

The secondary coil sees a changing magnetic field;electrons experience a force and move;which induces a current

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45
Q

Why is iron used as the core for a transformer?

A

Soft magnetic material; gains and loses magnetism easily.

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46
Q

What is the principle of conservation of energy

A

Energy cannot be created or destroyed; only changed from one form to another.

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47
Q

Magnets can attract or repel?

A

Other magnets

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48
Q

How is electricity generated in a generator?

A

A large coil is spun in a strong magentic field, this causes a force on the electrons and makes them flow producing a current.

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49
Q

Temperature, T

A

kelvin (K)

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50
Q

What happens to the resistance of a thermistor as it is heated

A

High temperatures reduces the resistance of a thermistor

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51
Q

Equation: charge, current and time

A

charge = current x time

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52
Q

What are the disadvantages of solar heating systems?

A

Unreliable (doesn’t work at night),may need additional boiler to produce hot water

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53
Q

What is Newton’s third law?

A

If object A exerts a force on object B, object B exerts an equal and opposite force on object A

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54
Q

Why do different planets have different values of g (gravitational field strength)

A

Planets with more mass (e.g. Jupiter) have a higher value of g

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55
Q

Equation: acceleration, change in velocity and time taken

A

acceleration = change in velocity ÷ time taken

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56
Q

What type of radioactive decay is most penetrating?

A

Gamma

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57
Q

gravitational potential energy, mass, g and height

A

gravitational potential energy = mass x g x height

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58
Q

What is felt when a current-carrying wire is in a magnetic field?

A

A force is felt when a wire carries a current in a magnetic field

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59
Q

Equation: work done, force and distance moved

A

work done = force x distance moved

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60
Q

weight, mass and gravitational field strength

A

weight = mass x gravitational field strength

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61
Q

Equation: primary voltage, secondary voltage, primary turns and secondary turns

A

primary voltage ÷ secondary voltage = primary turns ÷ secondary turns

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62
Q

Time, t

A

second (s)

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63
Q

Force

A

newton, N

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64
Q

Equation: force, mass and acceleration

A

force = mass x acceleration

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65
Q

What equation links momentum, mass and velocity?

A

Momentum = mass x velocity

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66
Q

What is the order of the EM spectrum

A

Radio, Microwave, Infra-red, Visible, Ultra-violet, X-ray & Gamma

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67
Q

How can you see the shape and direction of a magnetic field

A

Use plotting compasses

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68
Q

How would you find the volume of a small irregular object (e.g. a pebble)

A

submerge in water. The volume of water displaced = volume of pebble

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69
Q

Natural satellites (e.g. moons) and artificial satellites (e.g. Hubble) orbit what?

A

Planets

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70
Q

A galaxy is made up of…

A

Billions of stars

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71
Q

Equation: input current, input voltage, output current and output voltage

A

input current x input voltage = output current x output voltageIIVI = IOVO

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72
Q

How does a stretching seatbelt reduce injury

A

Increases collision time, lower deceleration (a=V/t), lower force (F=ma)

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73
Q

milli

A

1/1 000

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74
Q

Equation: charge, current and time

A

charge = current x time

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75
Q

How does a fuse work

A

When the current goes higher than the value of the fuse it melts. This breaks the circuit and stops current flowing

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76
Q

What happens to particles at absolute zero? What is the pressure? Why?

A

Paricles stop moving at absolute zero (no KE), pressure is zero as particles are not colliding with walls

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77
Q

Electrical hazards include….

A

Frayed cables, damaged sockets, water near sockets and metal objects in sockets

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78
Q

Mass

A

kilogram, kg

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79
Q

What part of the EM spectrum has the highest frequency (and energy)

A

Gamma has the highest frequency

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80
Q

What are the advantages of fossil fuels?

A

Reliable (not weather dependent),already established,high power output

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81
Q

What are the advantages of nuclear power?

A

Reliable (not weather dependent),already established,high power output

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82
Q

What are the energy transfers involved with nuclear power

A

nuclear ⇒ thermal ⇒ kinetic ⇒ electrical

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83
Q

What is the efficiency of this machine

A

useful output energy = 10Jtotal input energy = 100Jefficiency = 10/100= 0.1 or 10%

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84
Q

Density

A

kilogram per metre cubed, kg/m³

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85
Q

Area

A

metre squared, m²

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86
Q

Force, F

A

newton (N)

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87
Q

Give some useful uses of electrostatic charges

A

Paint spraying,Chimney precipitator (smoke cleaner),Photocopier,Ink Jet Printer

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88
Q

Frequency

A

hertz, Hz

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89
Q

Describe the arrangement and motion of particles in a solid

A

Regular pattern OR close packed;Vibration in position;Little space between particles

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90
Q

Volume, V

A

metre cubed (m³)

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91
Q

What are the disadvantages of nuclear power?

A

Produces long lasting radioactive waste which must be securely stored,mining hazardous

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92
Q

What part of the EM spectrum has the longest wavelength

A

Radio has the longest wavelength

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93
Q

What happens to the average speed of gas molecules as you heat a gas?

A

Average speed of gas molecules increases as you heat a gas

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94
Q

efficiency, useful energy output and total energy input

A

efficiency = useful energy output ÷ total energy input (also efficiency = useful energy output ÷ total energy output)

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95
Q

What are the general disadvantages of renewable sources of power?

A

Unreliable (weather dependent),large amount of land needed to replace a typical power station

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96
Q

Describe a transverse wave and give an example

A

Transverse waves travel at right angles to the oscillation which caused them. E.g. light, other EM waves, Mexican Waves

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97
Q

After two half-lives, how much of an original sample is left?

A

One quarter

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98
Q

What is the difference between scalar and vector quantities?

A

Vectors have a direction as well as a magnitude (size)

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99
Q

What happens to the resistance of an LDR as more light is shone on it?

A

Bright light reduces the resistance of an LDR

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100
Q

Equation: voltage, current and resistance

A

voltage = current x resistance

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101
Q

Mega

A

1 000 000

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102
Q

Wavelength

A

metre, m

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103
Q

How can magnetism be induced in a magnetic material?

A

Placing a magnet close to a magnetic material will induce magnetism in the magnetic material

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104
Q

List the 4 types of stored (potential) energies

A

Gravitational, Elastic, Nuclear, Chemical

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105
Q

Define the time period of a wave

A

Time period is how long it takes for a wave to pass a point

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106
Q

What has the following magnetic field shape?

A

Field around a current carrying wire

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107
Q

How can you find the frequency of a sound wave from an oscilloscope trace

A

Measure time period T (of one wave) Use f = 1/T (careful with milli seconds) e.g T = 3ms so f = 1/0.003 = 333Hz

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108
Q

What are the advantages of geothermal power?

A

Renewable,no air pollution,low running costs, no fuel costs

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109
Q

What type of radioactive decay is most ionising?

A

Alpha

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110
Q

Equation: pressure, force and area

A

pressure = force ÷ area

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111
Q

Equation: wave speed, frequency and wave length

A

wave speed = frequency x wave length

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112
Q

Equation: refractive index, angle of incidence, angle or refraction

A

n = sin i ÷ sin rrefractive index = sin (angle of incidence) ÷ sin (angle of refraction)

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113
Q

How are electromagnets made?

A

A coil of wire around an iron core

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114
Q

Equation: density, mass and volume

A

density = mass ÷ volume

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115
Q

Why are step up and step down transformers used in the National Grid?

A

Voltage stepped up (e.g 100x);Current drops by the same amount (100x lower);less power loss due to heating;Stepped down to be safe in homes.

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116
Q

What materials does conduction happen best in and why?

A

Solids; particles are close together so can pass energy quickly. Works best of all in metals due to free electrons.

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117
Q

How can air molecules move heavy smoke particles (Brownian motion)

A

lots of tiny, fast moving air molecules exert enough force on a smoke particle to change its direction

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118
Q

What’s wrong with -50K as a temperature?

A

You can’t have negative kelvin temperatures, absolute zero (0K) is the coldest temperature possible

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119
Q

What change of state happens during freezing?

A

liquid to solid

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120
Q

Resistance

A

ohm, ?

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121
Q

Equation: moment, force and perpendicular distance from pivot

A

moment = force x perpendicular distance from pivot

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122
Q

In what two ways can radioactive decay be detected?

A

By photographic film and by a Geiger-Müller (GM) Tube

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123
Q

What is the atomic number?

A

The number of protons

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124
Q

What experiment can be done to demonstrate charging by friction?

A

Rub a plastic rod with a cloth, show charge on coulombmeter or repel/attract other charged things.Rub a balloon on jumper / hair stick to wall.

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125
Q

Acceleration

A

metre per second squared, m/s², m/s/s

126
Q

Describe the motion of gas particles

A

gas particles move in a random fast motion

127
Q

Length

A

metre, m

128
Q

What makes something an elastic material

A

Material regains original shape once stretching force is removed

129
Q

Equation: kinetic energy, mass and speed

A

kinetic energy = ½ x mass x speed²

130
Q

Our local galaxy is called

A

The Milky Way

131
Q

Maximum diffraction happens when the gap size is?..

A

similar to the wavelength

132
Q

Describe a longitudinal wave and give an example

A

Longitudinal waves travel parallel to the oscillation which caused them. E.g. sound

133
Q

What is the difference between Alternating Current (AC) and Direct Current (DC)

A

DC (direct current) only flows in one direction. AC (alternating current) constantly changes direction.

134
Q

Explain parallel circuits

A

Several routes for current to take, allows components to be switched on individually (e.g. lights at home), components get full supply voltage

135
Q

How does bending you knees help prevent injury?

A

Increases collision time, lower deceleration (a=Δv/t), lower force (F=ma)

136
Q

What are the disadvantages of hydroelectric power?

A

Floods a large area,disrupts people and animals

137
Q

Magnetically hard materials….

A

Are difficult to magnetise but keep their magnetism

138
Q

Waves transfer ……………………………… without transferring ……………………….

A

Waves transfer energy and information without transferring matter

139
Q

List the 5 types of non stored energies

A

Light, sound, thermal, kinetic, electrical

140
Q

Give a danger and use for infra red

A

Danger = skin burns,Use = cooking and night vision equipment

141
Q

What type of radioactive decay emits a helium nucleus?

A

Alpha

142
Q

Potential Difference, V

A

volt (V)

143
Q

After four half-lives, how much of an original sample is left?

A

One sixteenth

144
Q

Radioactive activity, A

A

becquerel (Bq)

145
Q

weight, mass and gravitational field strength

A

weight = mass x gravitational field strength

146
Q

The frequency of a sound wave is linked to its?.

A

pitch

147
Q

Charge, Q

A

coulomb (C)

148
Q

What is the nature of an electric current in a metal conductor?

A

A flow of negatively charged electrons flowing from the negative side of a battery or power supply

149
Q

What happens to the current in a circuit when the resistance is decreased?

A

Current increases as resistance decreases

150
Q

How can you show current is flowing in a circuit

A

A bulb or LED will light when a current flows. Or use an ammeter (in series)

151
Q

Equation: refractive index, angle of incidence, angle or refraction

A

n = sin i ÷ sin r

152
Q

wave speed, frequency and wave length

A

wave speed = frequency x wave length

153
Q

Give a use for visible light

A

Seeing, optical fibres, photography

154
Q

What are the energy transfers involved with fossil fuels

A

chemical ⇒ thermal ⇒ kinetic ⇒ electrical

155
Q

Equation: energy transferred and work done

A

energy transferred = work done

156
Q

Radioactive activity

A

becquerel, Bq

157
Q

What are the natural sources of background radiation?

A

Radon gas, cosmic rays, the ground, food and drink

158
Q

What happens to the pressure acting in a fluid as you go deeper?

A

pressure increases as you go deeper into a fluid

159
Q

voltage, current and resistance

A

voltage = current x resistance

160
Q

Why does an object reach terminal velocity?

A

As the speed and drag increase, eventually weight = drag so no resultant force

161
Q

Give an example of an AC source and a DC source

A

Mains are an AC source. Batteries are DC sources

162
Q

moment, force and perpendicular distance from pivot

A

moment = force x perpendicular distance from pivot

163
Q

Why doesn’t DC work for transformers?

A

DC doesn’t change direction so the magnetic field is constant

164
Q

refractive index and critical angle

A

n = 1 ÷ sin crefractive index = 1 ÷ sin (critical angle)

165
Q

Frequency, f

A

hertz (Hz)

166
Q

Potential Difference

A

volt, V

167
Q

What isotope Carbon-14 often used for

A

radiometric dating; identifying how old something is based on the count rate of the carbon-14

168
Q

Give a danger and use for ultra violet

A

Danger = blindness and damage to surface cells,Use = flourescent lamps, security markings

169
Q

Acceleration, a

A

metre per second squared (m/s/s, m/s²)

170
Q

What happens to the current in series circuit as more bulbs are added?

A

More bulbs in series increases the resistance and decreases the current

171
Q

What is produced around a conductor when electrical current flows?

A

An electromagentic field is created when current flows

172
Q

How would you describe a uniform field (3 marks)

A

Field lines are straight, parallel and equally spaced in a uniform field

173
Q

What is the relationship between input and output power of a transformer?

A

Pprimary = PsecondaryIpVp = IsVs

174
Q

What are circuit breakers

A

Circuit breakers break the circuit when the current goes higher than a certain value. Unlike fuses, they can be reset once tripped.

175
Q

What type of radioactive decay can only be stopped by a few centimetres of lead?

A

Gamma

176
Q

What particle was fired at gold foil during Rutherford’s experiments. What charge did it have?

A

Alpha particle which has a positive charge

177
Q

Name some electrical insulators (high resistance, do not allow current to flow)

A

Plastic, wood, (pure) water

178
Q

Volume

A

metre cubed, m³

179
Q

If a car has 20 000J of kinetic energy, how much work do the brakes have to do to stop the car?

A

20 000J

180
Q

Equation: force, mass and acceleration

A

force = mass x acceleration

181
Q

The universe is made up of….

A

Billions of galaxies

182
Q

How can you prevent heat transfer by convection?

A

Trap the fluids (e.g. trapping air in wool). This prevents both conduction and convection.

183
Q

Equation: pressure difference, height, density and g

A

pressure difference = height x density x g

184
Q

After three half-lives, how much of an original sample is left?

A

One eighth

185
Q

How do radiators in your house heat a room (hint, not by radiation)

A

Radiators heat air which rises and produces a convection current. Cold air is drawn into the bottom of the radiator too.

186
Q

Power

A

watt, W

187
Q

What type of radioactive decay does not emit a particle?

A

Gamma

188
Q

Which support provides more force? Why?

A

Moments about the box are equal. A closer to box, so needs bigger force to provide same moment as B.

189
Q

Momentum

A

kilogram metre per second, kgm/s

190
Q

How do you convert from C to K?What is 20 °C in K?What is -40 °C in K?

A

Add 273,20 °C + 273 = 293 K,-40 °C + 273 = 233 K

191
Q

What materials does convection happen best in and why

A

Fluids (gases and liquids); particles must be free to move so can’t happen in a solid

192
Q

If an object has 100J of gravitational potential energy when on a shelf and falls off, how much kinetic energy does it have just before hitting the floor? What have you assumed?

A

100J. But we assume there is no air resistance (100% efficient)

193
Q

Why aren’t machines 100% efficient?

A

Typically some energy is lost to the surroundings as heat.

194
Q

Pressure, p

A

pascal, newton per metre (Pa, N/m²)

195
Q

Define frequency

A

Frequency is the number of waves going past a point per second

196
Q

Moment

A

newton metre (Nm)

197
Q

When the angle of incidence is less than the critical angle light is…

A

When the angle is less than the critical angle, light is refracted

198
Q

Describe the structure of a transformer

A

Two coils of wire wrapped around a laminated iron core

199
Q

How does convection produce wind?

A

Air is heated, expands, becomes less dense, rises, colder air rushes into the area of low pressure.

200
Q

Describe how thermal energy is transferred by conduction

A

Particles knock into each other and pass on the energy

201
Q

How can fires be prevented when refuelling aircraft (linked to electrostatic charge)

A

Attach Earthing strap (to discharge aircraft) before beginning to refuel

202
Q

Velocity (initial, final), (u,v)

A

metre per second (m/s)

203
Q

What are the disadvantages of solar cells?

A

Unreliable (doesn’t work at night or when cloudy),large area needed to replace a typical power station,inefficient

204
Q

Give a use for radio

A

Communictions and broadcast

205
Q

What are the energy transfers involved with solar heating systems

A

thermal ⇒ thermal

206
Q

efficiency, useful energy output and total energy input

A

efficiency = useful energy output ÷ total energy input

207
Q

Power, P

A

watt (W)

208
Q

What happens to the speed of an object as it falls?What happens to its drag?

A

Speed increases (resultant force downwards)drag increases

209
Q

Which way does light bend when it enters a material with a higher refractive index (e.g. air to glass)

A

Light bends towards the normal when it goes from air to glass

210
Q

What are the advantages of solar heating systems?

A

Renewable,no air pollution,low running costs, no fuel costs

211
Q

The rate of doing work is also known as?

A

Power

212
Q

The amlitude of a sound wave is linked to its?.

A

volume

213
Q

Length, l

A

metre (m)

214
Q

Explain series circuits

A

Only one loop, simple, if one component fails no current flows

215
Q

What are the disadvantages of wind power?

A

Unreliable (only works when windy),needs lots of land,visual pollution, a large number needed to replace a typical power station

216
Q

How can you produce a uniform magnetic field (3 marks)

A

Place two attracting bar magnet poles (N&S) close together, hold them in place to avoid them touching

217
Q

What change of state happens during condensing?

A

gas to liquid

218
Q

Give a danger and use for gamma

A

Danger = cancer, mutation,Use = sterilising food and medical equipment

219
Q

What are the disadvantages of geothermal power?

A

Only works in very specific places,deep drilling difficult and expensive

220
Q

Moment

A

newton metre, Nm

221
Q

Refraction is when a wave………………………..

A

…bends

222
Q

What change of state happens during melting?

A

solid to liquid

223
Q

What can happen to waves when they pass an edge or go through a gap?

A

Diffraction; waves spread out

224
Q

Forces can do what to an object?

A

Change speed, shape or direction

225
Q

What is the difference between analogue and digital signals

A

Analogue signals can have any value.Digital signals can ONLY be on or off

226
Q

What are the disadvantages of fossil fuels?

A

Release CO₂ and air pollution, mining hazardous

227
Q

When a wave is refracted what two things change

A

Speed and direction change during refraction

228
Q

Equation: momentum, mass and velocity

A

momentum = mass x velocity

229
Q

One Watt is equal to what?

A

1 watt is 1 joule per second

230
Q

What are the energy transfers involved with wind power

A

kinetic ⇒ electric

231
Q

What are the advantages of solar cells?

A

Renewable,no air pollution,low running costs, no fuel costs

232
Q

What force is felt by the charged particle

A

No force felt as particle is moving parallel to field.

233
Q

What is the easiest way to reduce risk of injury from microwaves, infra red, ultra violet or gamma

A

Avoid exposure

234
Q

What change of state happens during boiling?

A

liquid to gas

235
Q

Electric current

A

amp, A

236
Q

Magnetically soft materials…

A

Are easy to magnetise but lose their magnetism quickly

237
Q

Equation: work done, force and distance moved

A

work done = force x distance moved

238
Q

Magnets can attract?

A

Magnetic materials (and other magnets too)

239
Q

What type of radioactive decay can be stopped by a few centimetres of air?

A

Alpha

240
Q

How can electrostatic charge be used to clean smoke in a chimney?

A

Smoke particles charged by wires and attracted to charged plates

241
Q

What do the thumb and fingers represent when using Flemming’s Left Hand Rule?

A

thumb = force (direction of movement),First Finger = Field,seCond finger = Current

242
Q

Factors which affect thinking distance

A

Speed, awareness (tired, alcohol)

243
Q

What type of radioactive decay emits an electron?

A

Beta

244
Q

centi

A

1/100

245
Q

Temperature

A

kelvin, K

246
Q

How can you prevent heat transfer by conduction?

A

Use insulators (such as air)

247
Q

What are the energy transfers involved with solar cells

A

light ⇒ electrical

248
Q

Only appliances with what sort of case need an Earth wire?

A

Appliances with metal cases; if the live wire comes loose someone could get a shock without an Earth wire.

249
Q

Time

A

minute, hour, day, min, h, d

250
Q

How can you produce more electricity in a generator?

A

Stronger magnet, spin coil faster

251
Q

How can you increase the speed of a motor (or volume of a speaker)?

A

Stronger magnet, more current

252
Q

What types of radioactive decay do not change an isotope’s mass number?

A

Beta and Gamma

253
Q

Why is the image in a mirror virtual?

A

The image in a mirror can’t be projected onto a screen

254
Q

How can you visualise the shape of a magnetic field (3 marks)

A

Place magnet under paper, sprinkle iron filings on top of paper, gently tap paper so filings line up with field lines.

255
Q

Do isotopes have the same atomic number, or the same mass number?

A

Atomic number (number of protons)

256
Q

What is the relationship between force and extension for a spring

A

Force is directly proportional to extention (if force doubles extension doubles)

257
Q

Describe the arrangement and motion of particles in a gas

A

No pattern;Able to move freely/fast;Larger space between particles;

258
Q

What two pieces of equipment are needed to display a sound wave?

A

Microphone and oscilloscope

259
Q

Why is the iron core in a transformer laminated?

A

Prevents eddy currents;stops heating;keeps efficiency high.

260
Q

How does a material gain a positive electrostatic charge?

A

Object loses electrons to gain a positive charge

261
Q

How do gas particles exert pressure on a container

A

molecules collide with walls of container,exert a force,over a given area,pressure = force / area

262
Q

One volt is equal to one?..

A

One joule per coulomb

263
Q

What is double insulation

A

Appliances with plastic cases are double insulated; even if live wire comes loose inside, a user can’t be shocked

264
Q

Equation: refractive index and critical angle

A

n = 1 ÷ sin c

265
Q

Planets orbit what? What shape are their orbits?

A

Planets orbit stars (e.g. the Sun) in circular orbits

266
Q

Energy, E

A

joule (J)

267
Q

What type of radioactive decay can be stopped by a sheet of paper?

A

Alpha

268
Q

Charge

A

coulomb, C

269
Q

Where does an objects weight always act

A

Through its centre of gravity

270
Q

How can electrostatic charge cause a fire at a petrol station.

A

Charge builds up on car while drivinga spark when person touches car+ fuel vapour = explosion

271
Q

How do you convert from K to C? What is 300K in °C?What is 100K in °C?

A

Subtract 273,300K-273 = 27 °C,100K-273 = -173 °C

272
Q

When two objects with a positive electrostatic charge are close together they?

A

Repel as like charges repel

273
Q

Reflection is when a wave…………………………

A

…bounces off something

274
Q

What are the advantages of hydroelectric power?

A

Renewable,no air pollution,low running costs, no fuel costs

275
Q

More turns on the primary coil what sort of transformer?

A

Step down; voltage is bigger across the primary coil

276
Q

What materials does radiation happen best in and why?

A

Transparent (see through) materials; thermal radiation can be absorbed by some materials and pass through others.

277
Q

Name some scalar quantities

A

Speed,mass,volume,time,energy,charge,pressure,power

278
Q

What has the following magnetic field shape?

A

Field around a flat coil(looks like an owl)

279
Q

What is a magnetic field line?

A

A magnetic field line shows the direction of a magnetic field (N to S). Where lines are close together the field is strong.

280
Q

A charged partical experience no force due to a magnetic field when?

A

Moving parallel to field

281
Q

How can digital signals carry more information?

A

Multiplexing (e.g. different coloured light in fibre optics)Increase the frequency of the transmitter

282
Q

How does a material gain a negative electrostatic charge?

A

Object gains electrons to gain a negative charge

283
Q

What type of radioactive decay can only be stopped by a few millimetres of aluminium?

A

Beta

284
Q

average speed, distance and time

A

speed = distance ÷ timespeed = distance⁄time

285
Q

When a gas or liquid is at rest, what can you say about the pressure?

A

at a given depth, pressure in a fluid at rest acts equally in all directions

286
Q

Energy

A

joule, J

287
Q

Energy transferred per unit charge is known as?

A

Voltage

288
Q

Electric current, I

A

amp (A)

289
Q

What are the energy transfers involved with geothermal power

A

(nuclear) ⇒ thermal ⇒ kinetic ⇒ electric

290
Q

Define wavelength

A

Wavelength is the distance between two peaks or two troughs

291
Q

What are the dangers of ionising radiation?

A

Mutation and damage to cells and tissues

292
Q

What is conservation of momentum?

A

Momentum before a collision (or explosion) is equal to the momentum after. Assuming no external forces act.

293
Q

What is the mass number?

A

The total number of protons and neutrons

294
Q

The gradient of a velocity-time graph gives

A

Acceleration

295
Q

What has the following magnetic field shape?

A

Field around a solenoid (same shape as a bar magnet)

296
Q

If the kelvin temperature of a gas doubles, what happens to the pressure it exerts?

A

Pressure doubles too

297
Q

What are the energy transfers involved with water power

A

gravitational ⇒ kinetic ⇒ electric

298
Q

When a wire is moved through a magnetic field what happens?

A

A wire moving through a magnet causes a current to flow

299
Q

More turns on the secondary coil is what sort of transformer?

A

Step up; voltage is bigger across the secondary coil

300
Q

Area, A

A

metre squared (m²)

301
Q

What are the general advantages of renewable sources of power?

A

Renewable,no air pollution,low running costs, no fuel costs

302
Q

Give a danger and use for microwaves

A

Danger = internal heating of body tissue,Use = cooking and satellite communications

303
Q

What type of radioactive decay changes both an isotope’s mass number and its atomic number?

A

Alpha

304
Q

What is the role of the control rods in a nuclear reactor?

A

To control the rate of reaction by absorbing neutrons

305
Q

What is the force which opposes motion

A

Friction (e.g. against a road) or drag (e.g. moving through air)

306
Q

Describe how thermal energy is transferred by convection

A

Hotter regions of fluid expand, become less dense and float on colder regions

307
Q

What happens to the pressure of a gas in a sealed container when you heat it? Why?

A

Pressure increases when you heat a sealed container of gas,molecules move faster hitting walls harder and more often,more force exerted on same area,pressure increases

308
Q

density, mass and volume

A

density = mass ÷ volume

309
Q

What is the relationship between kelvin temperature of a gas and average kinetic energy its molecules?

A

Kelvin temperature is directly proportional to average kinetic energy.Doubling the temperature (in kelvin!) doubles KE

310
Q

What are some advantages of digital signals?

A

Can carry more informationEasier to clean the signal (remove noise)

311
Q

Equation: acceleration, change in velocity and time taken

A

acceleration = change in velocity ÷ time taken

312
Q

Define amplitude

A

Amplitude is the maximum displacement above the equilibrium

IGCSE Physics (AGR 2018/19) (1 decks)

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