7 Flashcards
1
Q
Phys: what are the 3 ways of accelerating
A
- Speeding up
- Slowing down
- Changing direction (because velocity is a vector quantity)
2
Q
Phys: what is the equation for acceleration
A
3
Q
Phys: how do you find distance on a velocity time graph
A
Area under the line
4
Q
Phys: what is a longitudinal wave
A
It is a wave where vibrations of the particles is parallel to the direction of the wave
5
Q
Phys: what is a transverse wave
A
Vibrations are perpendicular to the direction of energy transfer
6
Q
Phys: how do you calculate wave period
A
Wave period = 1/ frequency
7
Q
Phys: how do you calculate frequency
A
Frequency=number of oscillations/time
8
Q
Phys: how do you calculate wavespeed
A
Wavespeed = frequency x wavelength
9
Q
Phys: what is a rarefraction
A
This is a reduction in density
10
Q
Phys: what are p-waves
A
They are longitudinal pressure waves
11
Q
Phys: what happens to the particles after a longditudional wave passes through them
A
They stay in the same position as before the wave came
12
Q
Phys: what is wave period
A
It is the time for one wave to pass
13
Q
Phys: what are electromagnetic waves
A
They are transverse waves that travel at the same speed in the same medium, roughly 300,000,000 m/s in vaccum
14
Q
Phys: what are the 7 main types of electromagnetic wave is order of frequency from high to low
A
Gamma, x-ray, ultraviolet, visible, infrared, microwave, radiowave
15
Q
Phys: what are the uses of gamma waves
A
Medical therapy, astronomy, steralisation
16
Q
Phys: what are the uses of x-rays
A
To treat camcer and to diagnose injury
17
Q
Phys: what are the uses of ultraviolet rays
A
Sun tanning, disinfecting, photography for medicine and phorensics
18
Q
Phys: what are the uses of visible light rays
A
Screens, vision
19
Q
Phys: what are the uses of infrared rays
A
Tv remotes, security
20
Q
Phys: what are the uses of microwaves
A
Signal transmission
Heating up food 😋🥐
21
Q
Phys: what are the uses of radiowaves
A
Radio and communication
22
Q
Phys: what is the range of human hearing
A
20-20000Hz
23
Q
Phys: what is infrasound
A
Sound below 20Hz
24
Q
Phys: what is ultrasound
A
Sound above 20000Hz
25
Phys: what is a photon and how fast do they move
They are packets of energy and travel at 300,000,000 m/s in a vacuum
26
Phys: what is a wave
They vibrate and oscilate and transfer energy without transferring mass
27
Phys: what is the rest position for a wave also known as
Equilibrium
28
Phys: what is the speed of sound in air
330 to 340 m/s, the warmer the air the sound travels faster.
29
Phys: what happens to the speed of sound when the medium gets more rigid
The speed gets faster
30
Phys: how does adding particles to a gas container increase the pressure
Increased frequency of collisions between **particles** and **walls** so greater force per unit area
31
Phys: why does a container of gas get warmer when you condense it quickly
Because you do work on the gas creasing the ke and so heat
32
phys: what is the equation for force
F = MA
33
phys: what is the equation for frequency
Frequency = number of oscillations / time
34
phys: what is the equation for wave period
1 / frequency
35
phys: what is the equation for wave speed
36
phys: what is the rest point of a wave called
equilibrium
37
phys: describe the magnetic field around a flowing charge
It forms a magnetic field in concentric circles around the charge
38
phys: what happens to the magnetic field if you increase current
It increases
39
phys: what is a solenoid
It is a coil of wire
40
phys: describe the magnetic field of a solenoid with flowing charge
41
phys: what is the equation for pressure
Pressure = force x area
42
Phys: what is the: crest, trough, equilibrium/rest position, amplitude and wavelength of a wave
43
Phys: is momentum vector or scalar
Vector
44
Phys: what is the equation for momentum
45
Phys: how do you find distance traveled on a velocity time graph
Find the area under the line
46
Phys: what is happening at each point on the velocity time graph
- A - accelerating
- B- constant velocity
- C - accelerating
- D - constant velocity
- E - decelerating
47
Phys: what is an elastic object
It is an object that returns to its original shape and size when a compression/tension force is released. This is called elastic deformation.
48
Phys: what is a plastic object
It is an object that will not return to its original size and shape when a compression/tension force is released. This is called plastic deformation.
49
Phys: what is a tension force
A force that pulls apart
50
Phys: what are the 8 types of contact force
- friction
- drag
- air resistance
- water resistance
- tension/elastic
- normal contact
- thrust
- lift
51
Phys: what are the 3 non-contact forces
- gravitational
- magnetic
- electrostatic
52
Phys: what is an interaction pair of forces
It is a pair of forces that are equal and opposite
53
Phys: what is the centre of mass of an object
It is the place in an object where the weight appears to act from
54
Phys: what is the law of conservation of momentum
Momentum before and event = momentum after an event
55
Phys: what is inertia
The tendency to continue doing what your already doing
56
Phys: what are the properties of permanent magentisim
- they are always magnetic
- their magnetic field has a norths nod a South Pole
- when they are near a magnetic material they cause it to become a magnet
57
Phys: what are the 3 magnetic elements (+plus the other material you must know)
Nickel, iron, cobalt and you must know steel for the exams
58
Phys: what causes Magnetisim
Electron spins
59
Phys what does the electron spin look like in magnetic materials vs non magnetic ones
In magnetic materials the electron spins are in the same orientation, they are not in non magnetic materials
60
Phys: what is a magnetic domain
It is a region in a magnetic field where the magnetic fields are in a uniform direction
61
Phys: what are the properties of induced magnets
- they have a north and South Pole (temporarily) and a magnetic field
- they can **only** be attracted by magnets and not repeled
- they are only magnets in another magnetic field
62
Phys: descipribe the magnetic field inside a solenoid with flowing charge
It is strong and uniform
63
Phys: what is an inelastic collision
A collision where the objects have no elasticity and so collide and stay together
64
Phys: What is the equation for change in momentum
65
Phys: Why does a crash mat work to slow soften an impact
• Increasing time taken to stop, decreases the rate of change of momentum
• This reduced the force one the person
• Leading to less damage
66
Phys: what is the electromagnetic spectrum
- it is a collection of waves each of which exists over a variety of wavelengths
67
Phys: what do waves transfer
Energy and information
68
Phys: what is it called when a wave passes through a clear surface
It is **transmitted** through the surface
69
Phys: what type of wave has the longest wavelength
Radiowaves
70
Phys: what are the properties of waves with short wavelengths
- shorter distance
- more information
- less spreading out
71
Phys: how do antennae work
When an electromagnetic wave hits an ariel it induces an alternating current in the antennae with the same frequency as the wave, this allows for information to be transferred.
72
Phys: why are microwaves and not Radiowaves used for satellite communication
Because Radiowaves cannot penetrate the atmosphere and so microwaves have to be used.
73
Phys: how do microwaves heat food
They vibrate the water molecules in the food and so cause it to heat
74
Phys: why do microwaves not affect you
Because of the mesh that has a smaller diameter than the amplitude of the wave
75
Phys: what are the risks of uv radiation
Skin cancer and eyedamage(sunglasses)
76
Phys: what part of the human body can be ionised
**Not** the cells, the atoms in the cells
77
Phys: how are atoms ionised
- electron hit by ionising radiation
- gains enough energy to escape the atom
- this creates an ion
78
Phys: what does the plum pudding model of the atom look like
79
Phys: what does the nuclear model of the atom look like
80
Phys what does the Bohr model of the atom look like
Energy levels
81
Phys: what does the model of the atom that Chadwick developed look like
82
Phys: how are radio-waves produced
Radiowaves are produced by oscillating current in an arial or circuit with the same freq as the current
83
Phys: if light enters a denser or less dense medium and it doesn’t refract what angle has it entered or exited the medium
It has entered or exited at the same angle as the normal
84
Phys: toward what does light bend when it enters a denser medium
Toward the normal
85
Phys: toward what does light bend when it enters a less denser medium
Away from the normal
86
Phys: what is the incident ray
The incoming ray
87
Phys: what is the ray after the incident ray that in inside the new medium
Refracted ray
88
Phys: what is the ray exiting the material
Emergent/transmitted ray
89
How do you calculate change in momentum
Change in momentum = force x change in time, check
90
Phys: how do you calculate force with momentum
Force = (change in momentum)/time
91
Phys: what happens to all emitted waves when temperature is increased
The greater the intensity of all emitted waves and the peak emitted wavelength us shorter add photo
92
Phys: Phys: what happens to all emitted waves when temperature is decreased
The weaker the intensity of all emitted waves and the peak emitted wavelength us longer
93
Phys: why is the moon classes as a satellite
Because it orbits a planet
94
Phys: what magnetic field lines are closer together what is it called
Denser lines of flux
