Zusammenfassung der Ressource
P5 d-f OCR gateway GCSE
- D
- When two objects interact,
they exert an equal and
opposite force on each
other. (Turn the names
around to check you have
the right forces!)
- The downwards force on a
boy due to gravitational
attraction from Earth is equal
and opposite to the upwards
force on Earth due to the
gravitational attraction from
the
- If no external forces act,
the total momentum
before a collision is the
same as the total
momentum after a
collision (conservation).
- Particles in a
gas move
randomly.
- Pressure in gases is
caused by particles
colliding with each
other and the walls
of the container.
- Smaller volume or
higher temperature
increase the
pressure as the
particles hit the
container more
frequently.
- Pressure = force/area
- A rocket pushes hot
gas downwards, so the
gas pushes the rocket
upwards.
- E
- The highest frequency
radio waves are
microwaves. They are
next to each other in the
EM spectrum
- High frequency waves
are used to send
signals to
Geostationary
satellites as they can
penetrate the Earth’s
atmosphere. Low
frequency can be used
for low orbit satellites.
- Microwave signals are
sent from a transmitter,
then received and
amplified by the
satellite. Then the signal
is retransmitted to
Earth and picked up by
a receiver.
- The ionosphere is
a layer of charged
particles, high in
the atmosphere.
- Microwaves between
frequencies of 3GHz and
30GHz are used for
satellite communication
- Below 3GHz, the waves are
reflected from the ionosphere
- Above 30GHz the
waves are
scattered and
absorbed by the
atmosphere.
- Long wavelength
radiowaves diffract around
hills, so have a longer
range.
- F
- Constructive interference: waves add
together to give a larger
wave;peak+peak or trough + trough;
waves are in phase.
- Destructive interference: waves
subtract to give calm water/dark
area; peak + trough; waves
antiphase.
- Lasers are used to show
interference, as they are coherent
(waves in phase), with same
wavelength /frequency.
- Path difference is an even
number of
half-wavelengths in
constructive interference,
and odd number of half-
wavelengths in destructive
interference
- Polarised light has
oscillations only in one plane.