physics 2

• specific latent heat is the amount of energy needed to change the state of 1kg without changing its temperature
• each loop of the solenoid has its own magnetic field
• specific heat capacity is the amount of energy needed to raise the temperature of 1kg of a material by 1 degree
• specific heat of water: 1. use a mass balance to measure the mass of the insulating container 2. fill the container with water and measure the mass again
• solid to liquid- melting
• liquid to gas- evaporating
• solid to gas- sublimating
• liquid to soild- freezing
• gas to liquid- condensing
• electromagnetism- a current flowing through a long, straight conductor which creates a magnetic effect. you can see this by placing a compass near the wire. the compass will move to point in the direction of current
• transformers have 2 coils of wire called primary and secondary coils
• a step down transformers bring pd back down
• a step up transformer at power stations boost electricity p.d
• electricity flows through the primary coil, the magnetic field it produces a current in the 2nd coil
• all magnets have a magnetic field around them, the closer the lines are the stronger the magnetic field. area of magnetic field is where it can produce a force
• temporary magnetic materials: iron, steel, nickel, colbalt
• some materials only produce a magnetic field while they're in another magnetic field which are called temporary magnets
• when a temporary magnetic material is put in a magnetic field and becomes magnetic it is called an induced magnet
• a uniform magnetic field has the same strength and direction
• there is a uniform magnetic field between the north pole of one bar magnet and the south pole of another bar magnet
• neutral wire- blue: completes the circuit, electricity follows out the neutral wire, always at ov
• live wire- brown: carries the voltage, alternates between positive and negative
• earth wire- green and yellow: safety wire, carries current away if something goes wrong
• parallel circuits: current is shared between branches, if you remove a loop or it breaks the rest of the other loop will keep working
• power is the rate of energy transfer
• power is the amount of work being done every second
• energy stores: kinetic energy, thermal energy, chemical energy, gravitational potential energy, elastic potential, electrostatic, magnetic, nuclear
• ohms law states that the size of the current flowing through a component of resistance, is directly proportional to the potential difference across the component at constant temperature
• a.c- alternating current
• d.c- direct current
• in a.c suppllies the charges are constantly changing directiom
• the uk domestic supply is 230v
• the frequency of a.cis 50hz
• cells and batteries supply direct current
• d.c is where the charges only move in one direction its created by a direct voltage
• a thermistor is a resistor that changes with temperature. in hot conditions the resistance drops, in cool conditions the resistance goes up
• the resistance of an LDR changes as the intensity of light changes, in bright light the resistance is too low and in dark light the resistance is too high
• series circuits- same current flows through all components, if the circuit is broken all components stop working
• non contact forces- other forces can act between objects that arent touching
• contact forces- objects need to be touching for some types of forces to act