# P3 Revision Sheet

```P3 REVISION – CHAPTER 1 – MEDICAL APPLICATIONS OF PHYSICS
X-rays:
Explain what an x-ray is:
Describe some of the safety issues
with X-rays:
Ultrasound:
Describe how an ultrasound works: Explain how an ultrasound can be
used to measure distance:
Describe what a CT scanner is:
Lenses:
Describe how a convergent lens works:
Explain some of the therapeutic
uses of ultra sound:
Endoscope:
Describe how an endoscope works: Describe how we use endoscopes in
medicine:
Describe how a divergent lens works:
Describe how the lens works in the eye:
Refraction index:
sin π
The refractive index of the substance, π =
sin π
Where π is the angle of incidence and π is the angle of refraction.
KEY WORDS:
Refraction index
Endoscope
Charge-couple
Converging lens
device
Diverging lens
CT scanner
Principal focus
Transducer
Magnifying
A-scan
Focal length
Refraction
Image
Snell’s law
ASSESSMENT:
P3 REVISION – CHAPTER 2 – USING PHYSICS TO MAKE THINGS WORK
Moments:
Describe what a moment it:
Complete the equation:
Moment = ____ X perpendicular distance
from the line of the force
to the pivot
______ newtons
________
______
Nm
m
Centre of mass:
Describe what the centre of mass of an
object is:
Draw the centre of mass on these shapes:
Moments in balance:
When a see-saw is balanced:
• the anticlockwise moment due to W1
• the clockwise moment due to W2 about
the pivot = W2d2
Calculate W1, if W2 = 7.0N, d1 = 0.40m and
d2 = 0.25m
Circular motion:
Explain centripetal force and the factors
that affect it:
Stability:
Explain the following:
Tractor safety:
The pendulum:
Describe the motion of a pendulum:
Bus tests:
The frequency of the oscillations is the
number of complete cycles of oscillation per
second.
High chairs:
the time period =
(in seconds, s)
Hydraulics:
Describe how machines use hydraulics:
KEY WORDS:
The formula for pressure is:
Pressure (Pa or N/m2) =
πππππ (π)
ππππ (π2 )
Effort
Pivot
Line of action
Centre of mass
Equilibrium
Moments
Resultant
Pressure
Pascal (Pa)
Hydraulic
Centripetal
Oscillation
Amplitude
Frequncy
1
πππππ’ππππ¦ ππ π‘βπ ππ ππππππ‘ππππ  (ππ βπππ‘π§,π»π§)
ASSESSMENT:
P3 REVISION – CHAPTER 3 – USING MAGNETIC FIELDS TO KEEP THINGS MOVING
Explain how an electromagnet works:
Explain Fleming’s left hand rule:
Explain electromagnetic induction:
The transformer equation is:
ππ πππππ π  πππππππ¦,ππ
ππ ππππ π  π ππππππππ¦,ππ
=
ππ’ππππ ππ π‘π’πππ  ππ πππππππ¦,ππ
ππ’πππππ  ππ π‘π’πππ  ππ π ππππππππ¦,ππ
If the transformer is 100% efficient:
πππ€ππ π π’ππππππ π‘π π‘βπ π‘ππππ ππππππ = πππ€ππ πππππ£ππππ ππ¦ π‘βπ π‘ππππ ππππππ
πππππππ¦ ππ &times; πππππππ¦ ππ’πππππ‘ = π ππππππππ¦ ππ &times; π ππππππππ¦ ππ’πππππ‘
ππ &times; πΌπ = ππ &times; πΌπ
Explain how an electric motor works:
Explain how a transformer works:
KEY WORDS:
South pole
North pole
Magnetic pole
Magnetic field
lines
Motor effect
‘Split-ring’
commutator
Induction
Transformer
National grid
Step-up
transformer
Step-down
transformer
ASSESSMENT:
```