P10: Need to know terms and formulae Flashcards
Nemonic for remembering electromagnetic spectrum
Rich Men Invent Very Unusual Xray Guns
In order of decreasing wavelength (i.e. largest to smallest wavelength)
- Radiowaves
- Microwaves
- Infrared waves
- Visible light
- ultraviolet waves
- Xrays
- Gamma Rays
Tool to remember circuit calculations
- Draw 5 triangles in the order shown in the diagram
- place one unit symbol at each vertex of each triangle and between the vertices of adjacent triangles starting from the left and in an up-down pattern.
- The symbols to be selected are taken from the nemonic:
Can Julie Visit W***_atson _***A***_nd _***C***_arry _***S***_ome _***Jellybeans With A***_ssorted _***Raisins?
Each triangle represents a triangle formula
What is a solar cell?
Electrical cell that produces a voltage when in sunlight.
What is specific heat capacity?
Energy needed by 1kg of the substance to raise its temperature by 1 Kelvin.
What is a solar heating panel?
Sealed panel designed to use sunlight to heat water running though it.
What is alpha radiation?
Alpha particles consisting of two protons and two neutrons emitted by unstable nuclei.
What is beta radiation?
Beta particles that are high-energy electrons created in and emitted from unstable nuclei.
What is gamma radiation?
Electromagnetic radiation emitted from unstable nuclei in radioactive substances.
What is the half-life of a radioactive isotope?
Average time taken for the number of nuclei of the isotope in a sample to halve.
What is nuclear fission?
The process in which certain nuclei spilt into two fragments, releasing energy and two or three neutrons as a result.
What is nuclear fusion?
The process in which small nuclei are forced together so they fuse with each other to form a larger nucleus.
What is activity?
The number of atoms of a radioactive substance that decay each second.
What is an atomic nucleus?
Tiny positively charged object composed of protons and neutrons at the centre of every atom.
What is a CT scanner?
A medical scanner that uses X-rays to produce a digital image of any cross section through the body or an organ.
What is an atomic number?
The number of protons in an atom.
What is ionisation?
Any process in which atoms become charged.
What is alternating current?
Electric current in a circuit that repeatedly reverses its direction.
What is a circuit breaker?
An electromagnetic switch that opens and cuts the current off if too much current passes through it.
What is a Coulomb?
-The unit of electrical charge. -Equal to the charge passing a point in a circuit in 1 second when the current is 1A.
What is direct current?
Electric current in a circuit that is in one direction only.
Define earthed.
Connected to the ground by means of a conducting lead or wire.
What is electric current?
-Flow of electric charge. -The size of an electric current is the rate of flow of charge.
What is electrical energy?
Energy transferred by the movement of electrical charge.
What is electromagnetic induction?
The process of inducing a potential difference in a wire by moving the wire so it cuts across the lines of force of a magnetic field.
What are electromagnetic waves?
-Electric and magnetic disturbances that transfer energy from one place to another. -The spectrum is ordered in increasing wavelengths.
What is frequency of an alternating current?
The number of complete cycles an alternating passes through each second.
What is a fuse?
A fuse contains a thin wire that melts and cuts the current off if too much current passes through it.
What is a kilowatt?
1000 Watts
What is a kilowatt-hour?
Electrical energy supplied to a 1kW electrical device in 1 hour.
What is a neutral wire?
The wire of a mains circuit that is earthed at the local sub-station so its potential is close to zero.
What is the North pole?
North-pointing end of a freely suspended bar magnet or of a magnetic compass.
What is Ohm’s Law?
The current through a resistor at constant temperature is directly proportional to the potential difference across the resistor.
What is an Ohmic conductor?
A conductor that has a constant resistance and therefore obeys Ohm’s law.
What is an oscilloscope?
A device used to display the shape of an electrical wave.
What is a parallel setup?
Components connected in a circuit so that the potential difference is the same across each one.
What is potential difference?
A measure of the work done or energy transferred to the lamp by each coulomb of charge that passes through it.
What is resistance?
-Resistance = pd / current -Opposition to the flow of an electric current.
What is a series setup?
Components connected in a circuit so that the same current passes through them.
What is the south pole?
South-pointing end of a freely suspended bar magnet or of a magnetic compass.
What is a split-ring commutator?
Metal contacts on the coil of a DC motor that connects the rotating coil continuously to its electrical power supply.
What is static electricity?
Charge “held” by an insulator or an insulated conductor.
What is a step-down transformer?
Electrical device used to step-down the size of an alternating voltage.
What is a step-up transformer?
Electrical device used to step-up the size of an alternating voltage.
What is a load?
-The weight of an object raised by a device used to lift the object. -The force applied by a device when it is used to shift an object.
What are magnetic poles?
Ends of a bar magnet or a magnetic compass.
What is the motor effect?
When a current is passed along a wire in a magnetic field and the wire is not parallel to the lines of the magnetic field, a force is exerted on the wire by the magnetic field.
What is amplitude?
-The height of a wave crest or a wave trough of a transverse wave from the rest position. -The maximum distance moved by an oscillating object from its equilibrium position.
What is an angle of incidence?
Angle between the incident ray and the normal?