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What’s a moment?
A turning effect of a force
What’s argon gas from?
Radiation of 40K in rocks
What’s earthing?
When there’s a loose wire or metal case
So they have an earth wire to the ground
Creates a safe route for the current to go if the live wire touches the casing as u would get an electric shock
What jobs does the RCCB do?
The job of a fuse and earthing
What’s hookes law?
The extension is directly proportional to the force applied provided the limit of proportionality is not exceeded
What’s power?
Work done in a given time
What’s potential difference?
Work done per coulomb
How do x rays work?
They are from an electron hitting a metal block to emit radiation
They are transmitted by soft tissue and absorbed by metal and bone
What’s ultra sound?
Sound waves above the frequency of human hearing 20-20000hz
Why does a CT have a high resolution?
Detailed
Narrow beam
CCD not a film
Why does a CT have a high contrast?
Removes scattered rays
Removes rays that aren’t absorbed
What’s accommodation?
How your eye changes to focus on things are different distances
What effects the focal length?
Refractive index
Curvature
If you have a large refractive index what does that need for the glasses?
They can be thinner
What’s total internal reflection?
The angel doing in is greater than the critical angle
More to less dense
What’s Newton’s first law?
Objects continue in a state of rest or uniform motion in a straight line unless the forces are unbalenced
Describe a transformer?
2 sets of coils made from copper
Covered in plastic insulation
With a soft iron core in the middle
How does a transformer work?
AC Changing current Change field In iron core Cuts through second coil Creating a voltage
Equation for transformers?
Primary voltage/secondary voltage= coils on primary/coils on second
What’s a switch mode transformer?
Higher frequency
Lighter and smaller
Less power used when there’s no load so less energy wasted
How do loud speakers work?
Current though the coil makes a field
This interacts with the permanent magnet
Motor effect- a wire with a current that cuts through a field feels a force
This interaction makes a force so it moves
AC current causing change in field so change in force direction
Vibrations
What’s com?
The point at which the mass is thought to be concentrated
