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Physics Flashcards

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1
Q

Induction

A

Process in which an object is charged without coming in contact with it

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2
Q

Polarisation

A

separation of positive charges

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3
Q

pd def

A

amount of energy required to move one unit of charge from one point to another

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4
Q

resistance

A

resistive force hindering the flow of electrons

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5
Q

voltage in series

A

added

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6
Q

voltage in parallel

A

same

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7
Q

current in series

A

same

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8
Q

current in parallel

A

added

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9
Q

resistance in series

A

added

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10
Q

resistance in parallel

A

1/R=1/R1+1/R2+1/R3

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11
Q

cell voltage in series

A

added

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12
Q

current

A

rate of flow of electric charge through a circut

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13
Q

physics formulae for p(resistivity)

A

p=R*L/a

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14
Q

p(resistivity) forula 2

A

p = R+A^2

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15
Q

Ohms law

A

v
___
(r*i)

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16
Q

4 triangles in physics

A

(((v))) . (((q))) . (((e/w))) . (((e/w)))
(r * I) . (I * t) . ((t * p)) . ((q *v))

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17
Q

diode

A

controls direction of current

high resistance in other direction

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18
Q

wires

A

brown = live
blue = neutral (0 V)
green/yellow/red = earthing

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19
Q

brown wire

A

live wire

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20
Q

green yellow red wire

A

earthing wire

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21
Q

blue wire

A

neutral wire (0 V)

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22
Q

Ferromagnet

A

metal alloy that can be magnetised

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23
Q

non-magnetic metals

A

zinc copper brass tin aluminium

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24
Q

Faradays law

A

induced emf is directly proportional to the rate of change in magnetic field

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25
Q

Lenz law

A

induced current flows in opp direction to charge produced

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26
Q

flemings right hand rule vs left hand

A

right hand = generator

left hand = motor

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27
Q

Non-ferrous/Non-magnetic
materials Examples

A

Plastic Wood Rubber

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28
Q

Ferrous/Magnetic
materials
Examples

A

Iron nickel cobalt

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29
Q

Avg speed formula

A

Total dist/time

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30
Q

Why is avg speed diff from actual speed

A

For them to be equal the actual speed should be constant

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31
Q

What is velocity

A

Includes the speed and the direction of travel

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32
Q

What quantity is velocity

Scalar or vector

A

Vector quantity

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33
Q

Diff between vector and scalar quantities

A

Vectors have magnitude and direction, scalars only have magnitude.

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34
Q

Isotopes def

A

Element having same no of protons but diff no of neutrons

Same chemical propertie

They have diff masses, diff physical properties

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35
Q

Atomic no (Z)

A

Proton no (no of protons)

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36
Q

Mass no (A)

A

Nucleon no

No of protons + neutrons

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37
Q

a
____X
z

A

a = mass no
x = element symbol
z = atomic no

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38
Q

nucleur radiation def

A

Tiny particles and waves of energy that radiate from an unstable and disintegrating nucleus

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39
Q

Radioactive material

A

Material which emits nucleur radiation (tiny particles and waves of energy)

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40
Q

Radioactive decay

A

Disintigration of unstable nuclei

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41
Q

Eg of stable isotopes

A

Carbon 12 & 13
Potassium - 39

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42
Q

Eg of unstable nucleus

A

Carbon-14
Potassium - 40
Uranium - 234, 235 & 238

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43
Q

Ionizing effect

A

Nucleur radiation can remove electrons from atoms in its path. This is called the ionizing effect

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44
Q

What happens if gas is ionized

A

Its conducts electricity

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45
Q

What happens if living things are ionized

A

Cells are destroyed or damaged

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46
Q

Radiation can be dectected by

A

Geigher -Müller tube

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47
Q

Charges of radiation

A

Alpha = +2
Beta = -1
Gamma = 0

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48
Q

Speed of gamma

A

Speed of light

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49
Q

Speed of alpha

A

0.1 *speed of light

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50
Q

Speed of beta

A

0.9 * speed of light

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51
Q

Main source of background radiation

A

Radon from ground

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52
Q

Radioactive decay

A

A radioisotope (unstable arrangement
of neutrons and protons) is altered to make a more
stable arrangement.

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53
Q

Half-life of a radioisotope:

A

Half-life of a radioisotope: is the time taken for half the nuclei present in any given sample to decay

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54
Q

Activity (radioactivity) Definition

A

The no of disintegrations per second in a radioactive sample

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55
Q

Activity (radioactivity) SI Unit

A

becquerel (Bq)

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56
Q

Beta - does what

A

Converts neutrons to protons

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57
Q

Beta + does what

A

Converts protons to neutrons

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58
Q

Alpha emmision used to make what stable

A

Heavy isotope (proton no >83)

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59
Q

Rutherford’s Experiment

A

Rutherford concluded that the atom must be largely
empty space, with its positive charge and most of its
mass concentrated in a tiny nucleus.

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60
Q

Safety Precautions
with radioactive materials

A
  • Radioactive material is stored in a lead container
  • Picked up with tongs, not bare hands
  • Kept away from the body and not pointed at people
  • Left out of its container for as short a time as possible
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61
Q

BROWNIAN MOTION

A

Gas molecules move randomly. This is because of
repeated random collisions with other gas molecules,
which constantly change the direction they move in.
Small molecules move much faster and have higher
energy than larger molecules. They can effectively move
large molecules due to repeated random bombardmentthis can be seen by larger smoke particles moving.
Therefore, the random motion of particles in a
suspension is evidence for the kinetic molecular model of
matter.

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62
Q

Micrometer screw gauge measures what?

A

Diameter of wire or thickness of glass

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63
Q

Vernier calliper measures what?

A

dist between two sides of a surface

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64
Q

Density formula

A

Mass/volume

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65
Q

Power formula

With pd and current

A

P = V * I

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66
Q

Flemings left hand rule is for

A

DC Motors

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67
Q

How can we figure out direction of the wire turning in Dc motors

A

Fleming left hand rule

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68
Q

How can we figure out direction of the wire turning in AC Genrator

A

Fleming right hand rule

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69
Q

Flemings right hand rule is used for

A

AC Genrators

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70
Q

Negative acceleration is also called

A

Deceleration

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71
Q

Acceleration

A

Change in velocity (Δv) over the change in time (Δt),

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72
Q

Acceleration formula

A

((Final speed + initial speed)/2)*time

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73
Q

When deceleration is caused
by air resistance

A

acceleration by gravity

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74
Q

Mass definition

A

A measure of matter in a body and the body’s resistance to motion

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75
Q

Weight definition

A

Weight is the force of gravity on a body as a result of its mass

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76
Q

Weight formula

A

Mass * G (acc due to gravity)

Acceleration due to gravity = 9.8m/s^2

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77
Q

SI unit of mass

A

Kilogram (kg)

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78
Q

SI unit of weight

A

SI unit is Newton (N)

which is the same as kg⋅m/s2

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79
Q

Density (p) formula

A

Mass (m) / Volume (V)

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80
Q

What is density

A

The amount of matter in a fixed volume of a body

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81
Q

How to find mass of liq

A

To find the mass of the fluid,
weigh it in a container, pour it out, weigh the empty container, and subtract the mass of the empty container from the full container.

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82
Q

How to find volume of liq

A

To find the volume of the fluid, you simply measure it very carefully in a graduated cylinder.

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83
Q

Find mass of solid

A

Use balance to find weight

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84
Q

To find volume of irregular obj

A

To find out volumeof an irregular object,
put object into a measuring cylinder with water and the rise of water is the volumeof the object.

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85
Q

Lower density floats or sinks

A

Lower density floats

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86
Q

Force formula

A

Force = Mass * Acceleration

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87
Q

Newton definition

A

1 newton is the force required to give 1kg an acceleration of 1m/s^2

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88
Q

Friction def

A

Friction:
the force between two surfaces which impedes motion and results in heating

Eg - Air resistance

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89
Q

Newtons first law

A

If no external force is acting on it, anobject will, if stationary, remain stationary, and if moving,keep moving at a steady speed in the same straight line.

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90
Q

Newtons second law

A

F = ma

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91
Q

Newtons third law

A

if object A exerts a force on object B,then
object B will exert an equal but opposite force on object A

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92
Q

An object at steady speed in circular orbit is always accelerating even though speed is constant. How?

A

as its direction is changing, but it gets nocloser to the center.

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93
Q

Centripetal force Definition

A

Centripetal force is the force acting towards the center of a circle.

It is a force that is needed, not caused, by circular motion.

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94
Q

Eg of centripetal force

A

For example, when you swing a ball on a string round in a circle, the tension of the string is the centripetal force.

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95
Q

When you swing a ball on a string round in a circle, the tension of the string is the centripetal force.

If the string is cut then how will the ball travel (related to direction) ?

A

If the string is cut then the ball will travel in a straight line at a tangent to the circle at the point where the string was cut.

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96
Q

Centrifugal force definition

A

Centrifugal force is the force acting away from the center of a
circle.

The centrifugal force is the reaction to thecentripetal force.

It has the same magnitude (amt of force) but opposite direction to centripetal force.

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97
Q

Eg of Centrifugal force

A

When a car in motion takes a sudden turn towards left, passengers in a car experiences an outward push to the right.

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98
Q

Centrifugal vs Centripetal force

A

Centripetal force is the force acting towards the centre of the circle.

Centrifugal force is the force acting away from the centre of the circle.

Centripetal force is needed for circular motion. Centrifugal force is caused by centripetal force.

Both have the same magnitude but act in opp diections.

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99
Q

A Moment definition

(force and motion)

A

A moment is a measure of the turning effect on a body

100
Q

Moment formula

(force and motion)

A

Moment (Nm) = Force (N) * Perpendicular dist from centre (m)

A moment is a measure of the turning effect on a body

101
Q

Ways to increase moment of force

A
  • Increase dist from centre
  • Increase force
102
Q

levers are force magnifiers as

A

Turning a bolt is far easier with a wrench because the perpendicular distance from pivot is massively increased, therefore so is the turning effect

103
Q

Equilibrium

A

the condition of a system when neither its state of motion nor its internal energy state tends to change with time.

In equilibrium,
clockwise moment = anti clockwise moment

there is no resultant force acting on the body.

104
Q

How can equilibrium be proven

A

This can be proven by hanging masses of the same weight on opposite sides of a meter rule on a pivot at equal distances from the pivot showing that the meter rule in stationary.

105
Q

Centre of mass definition

A

Centre of mass: imaginary point in a body where total mass of body seems to be acting.

Eg in sphere, its at the exact ce

Mass on all sides of the pt are equal

106
Q

Scalar quantity

A

A scalar is a quantity that only has a magnitude (so it be positive) for example speed.

107
Q

Vector quantity

A

A vector quantity has a direction as well as a magnitude,for example velocity, which can be negative.

108
Q

Momentum formula

A

mass *velocity

strength or force gained by motion or by a series of events

109
Q

What is momentum

A

strength or force gained by motion or by a series of events

110
Q

what is the principle of conservation of momentum

A

The principle of conservation of momentum states that if two objects collide, then the total momentum before and after the collision will be the same if there is no external force acting on the colliding objects.

mA uA+mB uB = mA vA+mB vB
m=mass
u=Initial Velocity
v = final velocity

111
Q

What is impulse

A

Impulse is a certain amount of force you apply for a certain amount of time to cause a change in momentum.

112
Q

Impulse formula

Impulse symbol = J or IMP

A

IMP(J) = F(force) x t(time)
or = mv − mu (change in velocity)

Amt of force applied for amt of time causing change in momentum

Impulse

product of force and time for which it acts

113
Q

Energy definition

A

Energy:
amount of work and its measured in Joules (J)

An object may have energy due to its motion or itsposition

114
Q

SI Unit of energy

A

Joules (J)

115
Q

What is conservation of energy

A

Conservation of energy: energy cannot be created or destroyed, when work is done, energy is changed from one form to another.

116
Q

Kinetic energy is formed due to what?

A

Kinetic energy is due to motion

117
Q

Gravitational energy

A

The potential of an obj to fall

118
Q

Where is chemical energy found

A

In chemical bonds

119
Q

What is nucleur energy

A

Atoms rearranged / split

120
Q

Internal energy is due to

A

the motion of molecules

121
Q

What is electrical energy

A

Energy carried by electrons

122
Q

What is light energy

A

Energy carried in light waves

123
Q

Sound energy

A

Energy carried in sound waves

124
Q

Kinetic energy formula

A

K.E. = 1/2 x M x V^2

0.5 x Mass x Velocity x Velocity

125
Q

Gravitational Potential energy Formula

G.P.E

A

G.P.E = mgh (mass x gravity x height)

g = acc due to gravity

126
Q

Efficiency definition

A

Efficiency: how much useful work is done with energysupplied

Due to the processes through which energy transferstake place not
being 100% effi cient, energy is lost to thesurrounding and
therefore energy gets more spread out(dissipated)

127
Q

Eficiency formula

A

(Useful energy output /Energy input ) x 100

or

(Useful power output /power input ) x 100

128
Q

Fuel Advantages and disadvantages

burnt to make thermal energy,makes steam, turnsturbine

A

Advantages
Cheap, Plentiful,Low-tech

Disadvantages
Harmful wastes:(Greenhouse/pollutant gas,
Radiation)

129
Q

Wave energy: (advantages and disadvantage )
generators driven by up and down motion of waves at sea.

A

+No greenhousegases produced
- Difficult to build

130
Q

Tidal energy: (adv and disadvantages)
dambuilt where rivermeets sea, lake fi llswhen tides comesin & empties whentide goes out;water fl ow runsgenerator

A

+ No greenhousegases produced
- Expensive
- Can’t be built everywhere

131
Q

Hydroelectric: (+ & -)
river& rain fill up lake behind dam, water released, turns turbine ∴ generator

A

+ Low impact on environment
+ Energy produced at constant rate
- Few areas of theworld suitable

132
Q

Geothermal: (+ & - )
water pumped down to hot rocks rising as steam

A

+ No CO2 produced
- Deep drilling
- difficult and expensive

133
Q

Nuclear fission: (+ & -)
uranium atoms split by shooting neutrons at them

A

+ Produces a lot of energy with very little resources
- Produces radioactive waste

134
Q

Wind: (+ & -)
windmills are moved by the breeze. They generate electricity from kinetic energy.

A

+ No CO2/Greenhouse gasses produced
- Few areas of theworld suitable

135
Q

Solar panels:
absorbs energy and use it to heatwater

A

+ No CO2 produced
- Variable amount of sunshine in some countries

136
Q

Solar cells/photovoltaic cells: (+ & -)
made of materials that deliver electrical current when it absorbs light

A
    • No CO2 produced
  • Variable amount of sunshine in some countries
137
Q

When is work done

A

Work is done when force makes something move

138
Q

SI UNit of work

A

J (Joule)

139
Q

Work formula

A

Work (Nm) = Force (N) x Distance(m)

Nm (Newton metre) is the same as J (Joule)

140
Q

Δ means

A

change in something (eg ΔE means change in energy)

141
Q

Joule def

A

1 joule of work = force of 1 Newton moves an object by 1meter

142
Q

Power def

A

Rate of work

143
Q

SI unit of power

A

Watts (W)

144
Q

Power (w) formula

A

Work done (J) / Time taken (S)

145
Q

Pressure def

A

Force per unit area

146
Q

Pressure (Pa) formula

A

Force(N)/Area(m^2)

147
Q

SI Unit Pressure

A

Pascal (Pa)

Pa = N/m^2

148
Q

Pressure in liquids formula

A

p = ρ g h ,

p is the pressure,
h is the depth of the liquid,
ρ is the density of the liquid,
g is the acceleration due to gravity.

149
Q

What happens to pressure when depth of a fluid increases

A

Pressure increases

P =p g h

150
Q

Pressure is measured using

A

Manometer and Barometer

151
Q

What does manometer measure

A
  • Measures the pressure difference
  • The height diff erence shows the excess pressure in addition to the atmospheric pressure.

Pressure

152
Q

What does barometer measure

A
  • Tube with vacuum at the top and mercury filling the rest.
  • Pressure of the air pushes down on reservoir, forcing mercury up the tube.
  • Measure height of mercury
  • ~760 mm of mercury is 1 atm.

Measures atmospheric pressure in atm

153
Q

1atm in mm

A

1atm = 760 mm

154
Q

Evaporation

A

It is the escape of more energetic particles from thesurface of a
liquid

155
Q

What happens to the the liquids temp after most of it evaporates

A

If more energetic particles escape, the liquid contains few high energy particles and more low energy particles so the average temperature decreases.

So, a body in contact with an evaporating liquid will
subsequently cool.

156
Q

Evaporation can be accelerated by:

A
  • Increasing temperature: more particles have energy to escape
  • Increasing surface area: more molecules are close to the surface
  • Reduce humidity level in air (draught): if the air is less humid, fewer particles are condensing.

Evaporate
energetic particles (having high temp) escape
∴ temp is less

157
Q

How is pressure related to volume in a gas

A

Pressure is inversely proportional to volume

If the volume increases and the temperature stays constant, the particles hit the surface less often, thus decreasing the pressure.

158
Q

Why is pressure inversely proportional to volume of a gas

A

If the volume increases and the temperature stays constant, the particles hit the surface less often, thus decreasing the pressure.

P1 V1 = P2 V2
PV = constant

159
Q

Formula for changing pressure in gas

A

P1 V1 = P2 V2
PV = constant

The constant is valid at a fixed mass of gas at a constant temperature.

160
Q

How does the temp affect KE in gas

A

As the temperature increases of a fixed mass of gas, the pressure increases as the average kinetic energy increases…

161
Q

What happens to solids liquids and gasses on heating

A

They expand as the particles get more kinetic energy and move/vibrate faster and causes them to become further apart, taking up a greater volume.

162
Q

Expansion due to heat is the greatest in which state of matter

A

Gas then liquid then solid

Due to difference in molecular structure of different states of matter

163
Q

Frequency def:

A

the number of waves passing any point persecond
measured in hertz (Hz)

164
Q

Frequency:

A

the number of waves passing any point persecond
measured in hertz (Hz)

165
Q

More thermal energy is transfered if

A

The temp diff across opp ends of metal is increased

166
Q

Worst conductor in states of matter

A

gasses then liq

167
Q

Is water a good thermal conductor

A

No

168
Q

Conduction

A

Conduction
is the flow of heat through matter from places of
higher temperature to places of lowertemperature without movement of the matter as a whole. When material is heated, particles move faster, push neighbouring particles and those speed up too,
This way energy is transfered

Metals are good conductors as along with this they have many electrons that are looseand free that speed up when the metal is heated. As the electrons move freely, they collide with atoms, making them vibrate faster, therefore thermal energy is transfered to all parts.

169
Q

Conduction metals vs non-metals

A

In non-metals - when heat is supplied to something, its atoms vibrate faster and pass on their vibrations to theadjacent atoms.

In metals – conduction happens in the previous way andin a quicker way –electrons are free to move, they travelrandomly in the metal and collide with atoms and pass onthe vibrations Good conductors are used whenever heatis required to travel quickly through something

170
Q

Convection def

A

Convection
is the flow of heat through a fluid from places of
higher temperature in places of lower temperature by movement of the fluid itself.

171
Q

Does convection happen when water is heated at the top

A

When water is heated, it expands as particles move faster taking up more space making less dense

Since the water is at the top is less dense, it floats

172
Q

Convention current

A

As a fl uid (liquid or gas) warms up, the particles which arewarmer
become less dense and rise.
They then cool and fall back to the heat source, creating acycle
called convection current.
As particles circulate they transfer energy to otherparticles. If a
cooling object is above a fl uid it will create aconvection current
as well.

173
Q

Suns energy travels to us in the form of

A

electromagnetic waves
like infrared waves and light

This is also called thermal energy

174
Q

What does thermal radiation include

A

Mainly infrared waves but very hot objects also include light energy

175
Q

Emitters

A

Objects that send out thermal radiation

176
Q

Which colour is the best emmitter of thermal energy which and colour is the worst

A

Best - Black
Worst - white/silvery

This is bc white/silver reflect mst of the thermal energy away

177
Q

Why in hot countries houses are painted white

A

White reflects most of the thermal energy keeping the house cool

178
Q

Best colour for absorbing thermal enrgy

A

Best - black
Worst - silver/white

179
Q

Best and worst colour for reflecting thermal energy

A

Best - White/silver
Worst - black

180
Q

How to increase sensitivity in a thermometer

A

To increase sensitivity:
* Thinner capillary
* Less dense liquid
* Bigger bulb

181
Q

Ways to increase evaporation

A
  • Increase Temp (more particles get more energy to escape)
  • Increase Surface Area (more molecules collide with surface)
  • Reduce humidity (reduced water vapour content increases time taken for molecules to condense back to liquid)
  • Blow air across the surface (the air carries escaping water molecules away before they can return to liquid)
182
Q

Sublimation

A

Change from solid to gas

Eg - iodine crystals

183
Q

does evaporation cool/heat

A

evaporation cools as water droplets/vapour takes thermal energy away

184
Q

does evaporation cool/heat

A

evaporation cools as water droplets/vapour takes thermal energy away

185
Q

How does kinetic theory explain cooling effect of evaporation

A

If faster (hotter) particles escape the liquid, the slower (cooler) ones are left behind so temp reduces

186
Q

Specific heat capacity formula

A

Energy (J)/mass(kg)

187
Q

Frequence formula

A

1/period

188
Q

Period definition

A

Period:
time taken for one oscillation in seconds

189
Q

Wavelength: definition

A

Wavelength:
distance between a point on one wave to thecorresponding point on the next wave in length

190
Q

Amplitude def

A

Amplitude:
maximum displacement of a wave from itsundisturbed
point

191
Q

Speed of wavelength is measured in

A

Speed:
how fast the wave travels measured in m/s

192
Q

Wavefront def

A

Wavefront:
the peak of a transverse wave or thecompression of a
longitudinal wave

193
Q

Transverse waves

A

Transverse Waves
* Travelling waves in which oscillation is perpendicularto direction of travel
* Has crests and troughs
* For example, light, water waves and vibrating string

194
Q

Longitudinal waves

A

Longitudinal Waves
* Travelling waves in which oscillation is parallel to direction of travel.
* Has compressions and rarefactions
* For example, sound waves

195
Q

In wave speed formula

A

Speed (sec) = frequecy(Hz) x wavelength(λ)
(v = fλ)

Dist per sec = no of oscillations per sec * dist between wavefronts

196
Q

Wavelength symbol

A

λ

197
Q

λ

A

Wavelength

198
Q

Frequency unit

A

Hertz (Hz)

199
Q

Why does refraction happen

A

When waves change medium, they slow down,

Since (v=fλ) and frequency (f) should remain constant, decrease in speed causes decrease in wavelength (waves become closer to each other)\

When they become closer to each other, direction changes

200
Q

When do waves slow down

A

When they pass from a rarer to denser material

201
Q

When wave slows down, it refracts where in relation to normal

A

It refracts towards normal (i>r)

202
Q

When wave speeds up, it refracts where in relation to normal

A

It refracts away normal (i<r)

203
Q

Effect on wavelength from deep to shallow water

A

Deep water to shallow water:
speed decreases,
wavelength decreases,
and frequency remains constant

204
Q

Effect on wavelength from shallow to deep water

A

Shallow water to deep water:
speed increases
wavelength increases,
and frequency remains constant

205
Q

Reflection

A

Reflection:
* Waves bounce away from surface at same angle they strike it
* Angle of incidence = angle of refl ection
* The incident ray, normal and reflected ray all lie on the same plane.
* Speed, wavelength and frequency are unchanged by reflection

206
Q

Properties of virtual image formed by plane mirror

A
  • Image is the same size as the object
  • Image is the same distance from the mirror as object
  • A line joining corresponding points of the image and object meet the mirror at a right angle
  • Image is virtual: no rays actually pass through theimage and the image cannot be formed on a screen
207
Q

What causes sound

A

Vibration

208
Q

What type of waves is sound

A

Transverse

209
Q

What do sound waves need to exist

A

medium

210
Q

What states of matter can sound travel through

A

Solid, liquid and gas

211
Q

Which can happen to sound waves

Refraction and reflection and diffraction

A

Refraction and reflection

Sound waves can also be diffracted (as we can hear someone even though we cant see them)

212
Q

Sound waves can be seen by

A

Microphone and oscilloscope
(vibrations changed into electrical oscillations

produces waveform (graph))

213
Q

Speed of Sound depends on

A
  • Temp (more heat, more spped)
  • Medium (faster in solids, then liquids slowest in gases)

Doesnt depend on pressure of air

214
Q

Speed of sound formula

A

Dist travled(m)/time taken (s)

unit = m/s

215
Q

Which is faster speed of light or sound

A

Sound is slower than light
(eg - lightning and thunder (by 3 sec))

216
Q

Sounds are louder at night as

A

At night the ground cools faster
Sound waves travel slower in cool temp
So waves leaving the ground tend to bend closer back to the ground due to refraction

217
Q

Echo

A

Reflected sound a short time after it is produced

218
Q

Echo formula

A

Speed of sound = Dist/time
=(2 x dist from wall)/echo time

219
Q

Echo is used in

A
  • Parking sensors (detect how far obstacle is from car)
  • Echo sounder (measures depth of water under boat)
  • Radar (uses microwaves instead of soundwaves) (detects position of aircraft/ship by measuring time taken of echo to reflect back to itself)
220
Q

High pitch has what frequency

A

High pitch

221
Q

Low pitch has what frequency

A

Low pitch

222
Q

If pitch increases by one octave, frquency..

A

frequency doubles

223
Q

Doubling the amplitude in sound waves affects energy/sound by…

A

Energy/sound ifs four times of what it used to be

224
Q

Ultrasound Waves:

A

high frequency sound waves,

medically used to look at structures and organs inside thehuman body, i.e. to form an
image of a fetus in a pregnancy

225
Q

What happens to light when it hits a black surface

A

It is absorbed

226
Q

Properties of light

A
  • Form of radiation
  • travels in straight lines
  • transfers energy
  • travels as waves
  • can travel trough empty space
  • fastest thing there is
227
Q

Colour depends on what for eye

A

Diff wavelengths is diff colours

228
Q

Colour depends on what for eye

A

Diff wavelengths is diff colours

229
Q

Monocromatic light

A

Light of a single wavelength and colour

230
Q

Refractive index formula

A

spped of light in vaccum/speed of light in medium

231
Q

Effect of splitting of light in prism is called

A

Dispersion

232
Q

Diatomic

A

Having two atoms

233
Q

Does hcl prevent rust

A

No

234
Q

Electrolysis is used for

A

Most reactive

235
Q

Naturally found elements are (more/less reactive than elements found by electrolysis)

A

Naturally found elements are less reactive than elements found by electrolysis

236
Q

Which is stronger alloy or metal

A

Alloy is stronger

237
Q

Malleable

A

Hammered into shape without breaking

238
Q

Ductile

A

Can be drawn into wires

239
Q

Sonorous

A

Make a ringing noise when struck

240
Q

When reacting with cold h2o

A

The more reactive the elemet is the more violent the reaction is

If the element is not reactive, no reaction takes place

241
Q

Why are more reactive metals, harder to extract

A

They are more stable so they form compunds with strong bonds

242
Q

Soft metal

A

Sodium

243
Q

Metal that floats on water

A

Sodium

244
Q

Unreactive metal

A

Gold

245
Q

Metal oxides

acids/bases

A

Bases

246
Q

Metals react to form positive/negative ions

A

+ ions

247
Q

mgh vs PGH formula

A

mgh - PE potential energy

pgh - pressure in liq

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