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137 Cards in this Set
- Front
- Back
What is a mechanical wave? |
The oscillation of particles which cause a transfer of energy though a medium |
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What are 2 transverse waves? |
Water waves Light waves |
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What is a type of longitudinal wave? |
Sound |
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Are transfers waves perpendicular or parallel? |
Perpendicular |
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Are longitudinal waves perpendicular or parallel? |
Parallel |
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3 properties that X-rays have. |
short wave length highly penetrating highly ionising |
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Are X-rays light or sound? |
light |
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How are electromagnetic waves and mechanical waves different? |
mechanical waves need a medium to move through whereas electromagnetic waves do not |
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whats the wave length of an X-ray? |
around 1 nanometre |
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describe how X-rays work |
1. the x-rays are emitted towards the body 2. they transmit though soft tissue but are absorbed by dense bone 3. the x-rays not absorbed then hit the photographic film turning it black 4. areas that were absorbed come out white so you can see breaks or fractures |
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how do CT scans work? |
by emitting x-rays towards the body from all angles to create a 3D image |
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describe how CT scans work |
1. x-rays are emitted towards the body from all angles 2. the rays transmit though the body but are absorbed by more dense tissue and bone 3. x-rays reach detector containing CCD's which detect the various intensities of light. 4. CCD's then convert the light to a 3D image |
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what are CCD's? |
charged coupled devices |
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advantage of x-rays |
you can see breaks and fractures in bones |
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disadvantage of both x-rays and CT's |
they're highly ionising and they could alter the DNA and cause cells to divide and create a mutation/tumor |
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advantage of CT's |
you can see different tissues as well as bone |
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what does an oscilloscope do? |
it makes it able for us to see sound waves (longitudinal) as light (transverse) |
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does increasing the amplitude of the wave make the sound louder or quieter? |
louder |
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does increasing the wave length increase or decrease the pitch? |
decrease |
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whats the range of human hearing? |
20Hz to 20,000Hz |
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what is an ultrasound? |
a sound wave which is above the range of human hearing |
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what happens to the speed of an ultrasound if it changes mediums? |
it changes its speed |
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what is the equation to work out the speed of a wave? |
speed=frequency x wavelength v=f x WL |
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whats 2 uses for ultrasounds? |
1. ultrasound imaging (baby scans) 2. breaking down kidney stones |
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what happens when ultrasound waves meet a medium? |
some are refracted and some travel though |
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why does refraction happen? |
when light reaches the boundary at an angle one side of the ray hits first and speed up/slows down first so causes the light to change angle |
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when the light is going into a denser medium does it slow down or speed up? |
slows down |
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when the light is going into a denser medium does it slow down or speed up? |
speed up |
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what is Snell's Law? |
refractive index=sin(index)/sin(refraction) n=sin(i)/sin(r) |
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what happens if the angle of the light ray is smaller than the critical? |
it refracts |
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when the light refracts are 90 degrees (the normal) what is the angle of the light? |
the same as the critical |
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what happens in total internal refraction? |
the angle of the light is larger than the critical |
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what is the equation for the critical? |
critical=1/sin-1(refractive index) |
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what are uses of total internal refraction? |
used in optical fibers to transmit data at high speeds(fiber optic internet) endoscopes |
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what is a real image? |
a image that can be projected onto a screen were the rays of light meet |
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what is a virtual image? |
forms where the rays appear to come from, you must look though the lens at the other side to see the object |
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what is magnified and diminished? |
magnified= bigger diminished=smaller |
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what is inverted and upright? |
inverted= upside down upright= right way |
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whats is function of the iris? |
varies the size of the pupil varies depending on the amount of light entering the eye. |
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whats the function of the cornea? |
aids the lense in refracting light as a protective layer filtering out UV |
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whats the function of the pupil? |
a hole that varies in size due to the iris . this controls the amount of light entering the eye. |
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whats the function of the retina? |
converts light into electrical signals that the brain converts to images. |
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whats the function of the lens? |
changes shape in order to refract and converge light to the retina |
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whats the function of the cillary muscles? |
to change the shape or curvature of the lens in order to focus light on the retina. |
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whats the function of the suspensory ligaments? |
connnets muscles to lense |
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whats the same as a cornea and lens in a camera? |
lens |
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whats the same as a retina in a camera? |
CCD |
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whats the same as a pupil in a camera? |
aperture |
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if you are longsighted do you need a converged or diverged lens? |
converged |
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if you are shortsighted do you need a converged or diverged lens? |
diverged |
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what cause long-sightedness? |
eye ball being too short lens unable to focus |
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what causes short-sightedness? |
eye ball too long lens unable to focus |
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what is A?
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iris
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what is B?
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suspensory muscles
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what is C?
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retina
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what is D?
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optical nerve
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what is E?
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ciliary muscles
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what is F?
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cornea
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what is G?
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pupil
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what is H?
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lens
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if the image is closer does the curvature need to be larger or smaller?
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larger
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If the image is further away does the curvature need to be larger or smaller?
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smaller
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what is mass?
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a measure of how much matter something has- how many particles its made from
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where is the centre of mass thought to be?
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where the mass is most concentrated
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how do you find the centre of mass of a regular object?
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draw lines of symmetry
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what are the two ways to increase stability?
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lower the centre of mass make the base wider |
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what are 3 of the 5 types of error?
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measurement error anomalies random error systematic error zero error |
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how does increasing the amplitude of a swing effect the swing time?
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as the amplitude increases the swing increases
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how does increasing the string length effect the swing time?
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as it increases the swing time increaes
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what is a moment?(and messurement)
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a moment is the turning effect of a force, it is measured in NM (newton metres)
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what effects a moment?
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distance force acts from pivot magnitude of force applied |
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how does the length of the force to pivot effect the flexion?
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as the force gets further from the pivot the flexion increases
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how does the force applied effect the flexion?
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the more force applied the more flexion
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how do you make an object unstable?
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make the line of action outside of the object
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What happens when the centre of mass gets higher? |
The angle to tilt decreases |
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What happens when the centre of mass gets higher? |
The angle to tilt decreases |
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What is speed? |
The distance a object goes in a set time |
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What happens when the centre of mass gets higher? |
The angle to tilt decreases |
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What is speed? |
The distance a object goes in a set time |
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What is velocity? |
The speed of an object but in a particular direction |
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What happens when the centre of mass gets higher? |
The angle to tilt decreases |
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What is speed? |
The distance a object goes in a set time |
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What is velocity? |
The speed of an object but in a particular direction |
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What is the speed of an object in circular motion? |
Always the SAME |
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What happens when the centre of mass gets higher? |
The angle to tilt decreases |
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What is speed? |
The distance a object goes in a set time |
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What is velocity? |
The speed of an object but in a particular direction |
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What is the speed of an object in circular motion? |
Always the SAME |
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What is the velocity of an object in circular motion? |
Always CHANGING |
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Front (Term) |
-10 |
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Front (Term) |
-10 |
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Front (Term) |
0 |
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-10 |
|
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0 |
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What is centripetal force? |
A force on an object in circular motion which acts towards the centre |
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What the force acting on a car going round a corner? |
Friction |
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How do you increase the magnetic force in electromagnets? |
Increase current Increase magnet strength More wires/coils |
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What does the left hand rule do? |
Predict the direction of force |
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What does the forefinger represent in Flemings left hand rule? |
Field |
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What does the thumb represent in Flemings left hand rule? |
Movement |
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What does the second finger represent in Flemings left hand rule? |
Current |
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What's the definition of pressure? |
Force per unit area |
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What is pressure? |
Force over area |
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What is pressure measured in? |
N/m2 Or Pa |
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What is a property of liquid which enables it to be used for hydraulics? |
When pressure acts on a liquid it acts equally |
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What happens when you cut through a magnetic field with a wire? |
The electrons in the wire move and a current is induced |
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What's the force acting on a planet orbiting the sun? |
Gravity |
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Amount of current can be increased by? |
Increasing coils Increase magnet strength Faster movement |
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What's the force acting on an electron orbiting a nucleus? |
Electrostatic |
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When will centripetal force increase? |
Speed of object increases Mass of object increases Decrease the radius of circle |
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What is a magnetic field? |
A magnetic field is a region of space established around a magnetic object or moving charges particles in which magnetic objects experience a force |
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When charged particles move in a wire what is established? |
A magnetic field around the wire |
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What is a coil of wire? |
Solenoid |
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What shape of magnetic field would a solenoid produce? |
Same as a bar magnet |
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What can happen when you wrap a solenoid around a iron core? |
Create an electromagnet |
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What are uses of electromagnets? |
Scrap yard cranes Electric bell RCCB Circuit breakers |
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What the force acting on a car going round a corner? |
Friction |
|
How do you increase the magnetic force in electromagnets? |
Increase current Increase magnet strength More wires/coils |
|
What does the left hand rule do? |
Predict the direction of force |
|
What does the forefinger represent in Flemings left hand rule? |
Field |
|
What does the thumb represent in Flemings left hand rule? |
Movement |
|
What does the second finger represent in Flemings left hand rule? |
Current |
|
What's the definition of pressure? |
Force per unit area |
|
What is pressure? |
Force over area |
|
What is pressure measured in? |
N/m2 Or Pa |
|
What is a property of liquid which enables it to be used for hydraulics? |
When pressure acts on a liquid it acts equally |
|
What happens when you cut through a magnetic field with a wire? |
The electrons in the wire move and a current is induced |
|
What's the force acting on a planet orbiting the sun? |
Gravity |
|
Amount of current can be increased by? |
Increasing coils Increase magnet strength Faster movement |
|
What's the force acting on an electron orbiting a nucleus? |
Electrostatic |
|
When will centripetal force increase? |
Speed of object increases Mass of object increases Decrease the radius of circle |
|
What is a magnetic field? |
A magnetic field is a region of space established around a magnetic object or moving charges particles in which magnetic objects experience a force |
|
When charged particles move in a wire what is established? |
A magnetic field around the wire |
|
What is a coil of wire? |
Solenoid |
|
What shape of magnetic field would a solenoid produce? |
Same as a bar magnet |
|
What can happen when you wrap a solenoid around a iron core? |
Create an electromagnet |
|
What are uses of electromagnets? |
Scrap yard cranes Electric bell RCCB Circuit breakers |