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Question 1

What’s a moment?

Answer 1

A turning effect of a force

Question 2

What’s argon gas from?

Answer 2

Radiation of 40K in rocks

Question 3

What’s earthing?

Answer 3

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

Question 4

What jobs does the RCCB do?

Answer 4

The job of a fuse and earthing

Question 5

What’s hookes law?

Answer 5

The extension is directly proportional to the force applied provided the limit of proportionality is not exceeded

Question 6

What’s power?

Answer 6

Work done in a given time

Question 7

What’s potential difference?

Answer 7

Work done per coulomb

Question 8

How do x rays work?

Answer 8

They are from an electron hitting a metal block to emit radiation
They are transmitted by soft tissue and absorbed by metal and bone

Question 9

What’s ultra sound?

Answer 9

Sound waves above the frequency of human hearing 20-20000hz

Question 10

Why does a CT have a high resolution?

Answer 10

Detailed
Narrow beam
CCD not a film

Question 11

Why does a CT have a high contrast?

Answer 11

Removes scattered rays

Removes rays that aren’t absorbed

Question 12

What’s accommodation?

Answer 12

How your eye changes to focus on things are different distances

Question 13

What effects the focal length?

Answer 13

Refractive index

Curvature

Question 14

If you have a large refractive index what does that need for the glasses?

Answer 14

They can be thinner

Question 15

What’s total internal reflection?

Answer 15

The angel doing in is greater than the critical angle

More to less dense

Question 16

What’s Newton’s first law?

Answer 16

Objects continue in a state of rest or uniform motion in a straight line unless the forces are unbalenced

Question 17

Describe a transformer?

Answer 17

2 sets of coils made from copper
Covered in plastic insulation
With a soft iron core in the middle

Question 18

How does a transformer work?

Answer 18

AC 
Changing current
Change field
In iron core
Cuts through second coil
Creating a voltage

Question 19

Equation for transformers?

Answer 19

Primary voltage/secondary voltage= coils on primary/coils on second

Question 20

What’s a switch mode transformer?

Answer 20

Higher frequency
Lighter and smaller
Less power used when there’s no load so less energy wasted

Question 21

How do loud speakers work?

Answer 21

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

Question 22

What’s com?

Answer 22

The point at which the mass is thought to be concentrated