# P5 d-f OCR gateway GCSE

Mind Map by singu006, updated more than 1 year ago
 Created by singu006 over 5 years ago
533
12

### Description

This mind map has facts that you will need to know for your OCR GCSE Physics course, P5 d-f

## Resource summary

P5 d-f OCR gateway GCSE
1 D
1.1 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!)
1.2 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
1.3 If no external forces act, the total momentum before a collision is the same as the total momentum after a collision (conservation).
1.4 Particles in a gas move randomly.
1.5 Pressure in gases is caused by particles colliding with each other and the walls of the container.
1.6 Smaller volume or higher temperature increase the pressure as the particles hit the container more frequently.
1.7 Pressure = force/area
1.8 A rocket pushes hot gas downwards, so the gas pushes the rocket upwards.
2 E
2.1 The highest frequency radio waves are microwaves. They are next to each other in the EM spectrum
2.2 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.
2.3 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.
2.4 The ionosphere is a layer of charged particles, high in the atmosphere.
2.5 Microwaves between frequencies of 3GHz and 30GHz are used for satellite communication
2.6 Below 3GHz, the waves are reflected from the ionosphere
2.7 Above 30GHz the waves are scattered and absorbed by the atmosphere.
2.8 Long wavelength radiowaves diffract around hills, so have a longer range.
3 F
3.1 Constructive interference: waves add together to give a larger wave;peak+peak or trough + trough; waves are in phase.
3.2 Destructive interference: waves subtract to give calm water/dark area; peak + trough; waves antiphase.
3.3 Lasers are used to show interference, as they are coherent (waves in phase), with same wavelength /frequency.
3.4 Path difference is an even number of half-wavelengths in constructive interference, and odd number of half- wavelengths in destructive interference
3.5 Polarised light has oscillations only in one plane.

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