Triple Paper 1 Flashcards
(69 cards)
1
Q
What does a scalar quantity have?
A
A magnitude but no direction
2
Q
What does a vector quantity have?
A
A magnitude and a direction
3
Q
What is the difference between a scalar and a vector?
A
A scalar has only a magnitude but a vector has both (Magnitude and direction)
4
Q
Give some examples of vector quantities
A
Force Velocity Acceleration Momentum Displacement
5
Q
Give some examples of scalar quantities
A
Temperature Mass Energy Distance Speed Density
6
Q
What is velocity?
A
It is speed in a stated direction
7
Q
What is the equation for speed?
And it rearranged
A
Speed=Distance ÷ Time
Distance=Speed x Time
Time=Distance ÷ Speed
8
Q
How do you find the speed on a distance-time graph?
A
Work out the gradient
9
Q
What is the equation for acceleration?
A
acceleration = change in velocity ÷ time taken
10
Q
What is another way to determine the acceleration?
A
(final velocity)^2 – (initial velocity)^2
= 2 × acceleration × distance
V^2-U^2=2ax
11
Q
How do you calculate the acceleration of a velocity/time graph?
A
Work out the gradient
12
Q
How do you determine the distance traveled on a velocity/time graph?
A
Use the area between the graph line and the time axis (Under the graph)
13
Q
Describe a range of laboratory methods for determining the speeds of objects
A
Light gates,
Single light gate (length of the card),
Ruler and stopwatch
14
Q
What is the typical walking speed? What is the typical running speed? What is the typical cycling speed? What is the typical wind speed? What is the speed of sound?
A
Walking-1.5m/s Running-3m/s Cycling-6m/s Wind-3-20m/s (depending on how strong) Sound-330m/s
15
Q
What is the acceleration due to gravity on earth?
A
10m/s^2
16
Q
An object moving in a circular orbit at
constant speed has a changing _____, what?
A
Velocity
17
Q
What is inertial mass?
A
It is a measure of how difficult it
is to change the velocity of an object and is defined as the ratio of force over acceleration
18
Q
What is Newton’s third law?
A
It is when two bodies interact, they apply forces to one another that are equal in magnitude and opposite in direction. The third law is also known as the law of action and reaction.
19
Q
What is momentum?
A
A mass in motion
20
Q
What is the equation for momentum?
A
momentum= mass × velocity
P=MV
21
Q
Describe examples of momentum in collisions
A
Momentum is conserved in collisions and explosions . Conservation of momentum explains why a gun or cannon recoils backwards when it is fired. When a cannon is fired, the cannon ball gains forward momentum and the cannon gains backward momentum.
22
Q
What is the equation for Newton’s second law/ another equation for force
A
force= change in momentum ÷ time
23
Q
What the is the equation for gravitational potential energy?
A
change in gravitational potential energy = mass × gravitational field strength × height
24
Q
What is the equation for kinetic energy?
A
kinetic energy=0.5 × mass × (speed)2
25
What is a diagram to represent energy transfers?
Sankey diagrams
26
What is meant by conservation of energy?
Energy cannot be gained or lost only transfered
27
Why is there no net change to the total energy in a closed system?
Because no enrgy can be transferred my the surroundings and no energy can leave it means that the energy cannot change
28
Why does a mechanical processes become wasteful when they cause a rise in temperature so dissipating energy in heating the surroundings?
Because the heat loss is a waste of energy that could be used to help power other parts of the process, so it is considered wasteful
29
How in all system changes energy is
| dissipated so that it is stored in less useful ways?
Whenever there is a change in a system, energy is transferred and some of that energy is dissipated . Any energy that is not transferred to useful energy stores is said to be wasted because it is transferred to the surroundings.
30
Name ways to reduce unwanted energy waste
Lubrication-no friction
| thermal insulation-no heat lost
31
Describe the effects of the thickness and thermal conductivity of the walls of a building on its rate of cooling qualitatively
To reduce thermal energy transferred from a warm house, the walls can be built thicker, so the energy must travel further before it is transferred to the outside.
A building with walls of a high thermal conductivity will cool down faster than one with walls of a low thermal conductivity.
32
What is the equation for efficency?
Efficiently=total energy transfered / total enrgy supplied
33
How can efficency be increased?
This can be achieved by reducing wasted energy transfers so more of the input energy is usefully transferred. Mechanical devices can be made more efficient through lubrication to reduce the friction between moving parts of a machine and increase the amount of useful energy transferred
34
What type of wave is a sound wave?,And why
Sound waves are longitudinal and that the vibrations are along the same direction as the wave transfers energy.
35
What type of waves are vibrations in a guitar string?, And why
Is it a transverse wave, motion in which all points on a wave oscillate along paths at ri
36
What is know as ultrasound?
Sound with frequencies greater than
| 20 000 hertz?
37
What is know as infrasound
Sound with frequencies less than 20 hertz
38
How does sonar use ultrasound?
Sonar uses ultrasound to detect objects underwater
The sound wave is reflected off the ocean bottom
The time it takes for the sound wave to return is used to calculate the depth of the water
The distance the wave travels is twice the depth of the ocean
This is the distance to the ocean floor plus the distance for the wave to return
39
How does foetal scanning use ultrasound?
In medicine, ultrasound can be used to construct images of a foetus in the womb.Ultrasound waves are sent through the womb then the ultrasound waves are reflected back by different boundaries between tissues in the path of the beam
When we get these echoesthey generate electrical signals that are sent to the ultrasound scanner
Using the speed of sound and the time of each echo’s return, the detector calculates the distance from the transducer to the tissue boundary
By taking a series of ultrasound measurements, sweeping across an area, the time measurements may be used to build up an image
40
What is reflection?
An abrupt change in the direction of propagation of a wave that strikes the boundary between different mediums
41
What is refraction?
The change in direction of a wave passing from one medium to another caused by its change in speed
42
What is the total internal reflection?
It is when the angle of the incident ray is greater than the critical angle for that material
43
What is the law of reflection?
The law of reflection states that the angle of incidence equals the angle of reflection
44
What is the critical angle?
Waves going from a dense medium to a less dense medium speed up at the boundary between them. This causes light rays to bend when they pass from glass to air at an angle other than 90°. This is refraction.
Beyond a certain angle, called the critical angle, all the waves reflect back into the glass. We say that they are totally internally reflected.
?
45
What is the difference between specular and diffuse reflection?
Specular reflection is defined as light reflected from a smooth surface at a definite angle, and diffuse reflection, which is produced by rough surfaces that tend to reflect light in all directions
46
How is the colour of light related to differential absorption at surfaces?
The colour of light very much depends on how the surfaces absorb colour as if the surface absorebs every colour expect blue it would appear blue as it the being reflected back to our eyes
47
How is the colour of the light related to the transmission of light through filters?
There is he typical light absorbtion by the surfaces however now with a filter it will only let that colour through so if you shone a white light through a blue filter it would be blue as only the blue has gone past
48
How is power relateate to it focal length and shape
The power of a lens is defined as the reciprocal of the focal length.
49
What does a converging lens do and what does it help with?
In a converging lens, parallel rays of light are brought to a focus
This point is called the principal focus
The distance from the lens to the principal focus is called the focal length
This depends on how curved the lens is
The more curved the lens, the shorter the focal length
(This lens is sometimes referred to as a convex lens)
It helps long-sightedness
50
What does a diverging lens do and what does it help?
In a diverging lens, parallel rays of light are made to diverge (spread out) from a point
This lens is sometimes referred to as a concave lens
The principal focus is now the point from which the rays appear to diverge from
(It is a concave lens)
It helps correct short sightedness
51
What is the difference between a real and a virtual image?
A real image is an image that can be projected onto a screen. A virtual image appears to come from behind the lens
52
From what are alpha, β– (beta minus), β+ (positron), gamma rays
and neutron radiation are emitted from?
Unstable nuclei in a random process
53
What are ionising radiations
alpha, β– (beta minus), β+ (positron) and gamma rays
54
What is background radiation?
Low-level radiation caused by the earth, rocks, and everyday things that are considered a normal level and don't affect humans in any negative way
55
Describe the origins of background radiation from Earth and
| space
The origins of background radiation are the natural sources of background radiation including cosmic rays - radiation that reaches the Earth from space. rocks and soil - some rocks are radioactive and give off radioactive radon gas. living things - plants absorb radioactive materials from the soil and these pass up the food chain
56
How would you detect radioactivity?
Use photographic film and a Geiger–Müller tube
57
An alpha particle is equivalent to what?
It e is equivalent to a helium nucleus,
a beta particle is an electron emitted from the nucleus and a
gamma-ray is electromagnetic radiation
58
Compare alpha, beta, and gamma radiations in terms of their
| abilities to penetrate and ionise
Alpha is the most ionising but the least penetrating and Gamma is the least ionising yet the most penetrating and beta is the middle of both
59
Describe how and why the atomic model has changed over
time including reference to the plum pudding model and
Rutherford alpha particle scattering leading to the Bohr model
Started as a big ball of positive charge embedded with electrons, the Rutherford did the gold foil experiment he found that the mass of an atom is concentrated at its centre, and the nucleus is positively charged. Bohr adapted Rutherford's nuclear model. Bohr did calculations that led him to suggest that electrons orbit the nucleus in shells.And it has slowly evolved and got a little more precise
60
Describe the process of β– decay
Beta-decay occurs when, in a nucleus with too many protons or too many neutrons, one of the protons or neutrons is transformed into the other. In beta minus decay, a neutron decays into a proton, an electron
61
Describe the process of β+ decay
In positron emission, also called positive beta decay (β+-decay), a proton in the parent nucleus decays into a neutron that remains in the daughter nucleus, and the nucleus emits a neutrino and a positron, which is a positive particle like an ordinary electron in mass but of opposite charge.
62
What is the steady state theory?
It is that the Universe has always existed, and that the Universe is expanding and constantly creating matter as the Universe expands.
63
What is the theory of the big bang?
According to the Big Bang theory, about 13.8 billion years ago, the whole Universe was a very small, extremely hot and dense region. From this tiny point, the whole Universe expanded outwards to what exists today.
64
What evidence supports the big bang theory?
Red shift and Cosmic Microwave background radiation
65
What is red shift?
If the wavelength is longer than expected this is called a red-shift. If a source of waves is moving away the wavelength appears longer. A red-shift in the light from a star shows that the distance between us and the star is increasing. The bigger the red-shift the faster the star is moving away.(This provides evidence for the big bang theory because after a “bang” occurs all of the matter moves away from the point of origin)
66
What is Cosmic Microwave background radiation (CMB)
It is the remains of the thermal energy from the Big Bang, spread thinly across the whole Universe.
(remainance of the BBT)
67
What is the current accepted model of origin for the universe?
The Big Bang Theory
68
What is the Doppler effect
If something that emits a wave moves whilst it is doing so then the wavelength of the sound will become shorter as it is moving towards you, increasing the frequency, and stretched as it is moving away, decreasing the frequency.You will hear this as a change in pitch, getting higher as it approaches and lower as it moves away.
69
Explain how the discovery of the CMB radiation led to the Big
Bang theory becoming the currently accepted model
Because we know it is the remenanceof energy/matter spreading out across the universe
