paper 1 Flashcards
(27 cards)
what is specific heat capacity
the energy required to raise the temperature of 1kg of a substance by 1 degree
describe the specific heat capacity practical
-measure mass of metal block or water in a beaker using top pan balance
-place an electrical heater in the water or on the metal block
-measure initial temperature of substance using a thermometer
-turn on the electrical heater and set a timer, measure the pd and current using voltmeter and ammeter
- after set time, turn of electric heater and measure the final temperature, and calculate change in temperature using final- original
what is power
the rate of energy transfer- measured in watts (W)
what is efficiency
a measure of how much energy going into a system is used usefully
describe the insulation practical
pour hot water into a beaker and set a timer, stop the timer when the hot water falls to your chosen temperature
repeat this but using different types of insulation or different layers of the same insulation, each time using the same chosen temperature to see how long it takes the water to fall to this temperature
what is electricity
the flow of charge
what is a current
rate of flow of charge, flows from positive to negative - measured with ammeter
Columbus - C
what is potential difference
the measure of how much energy is transferred per coulomb of electrons - measured by voltmeter
what is resistance
the measure of how much a component / object resists the flow of current- ohms
what is a diode
only lets current flow in one direction.
-low resistance in the forward direction
-high resistance in the backwards direction
what happens in a series circuit
- total potential difference shared between all components
- current is the same for all components
- total resistance = sum of resistances - add together
what happens in a parallel circuit
- potential difference is the same for every branch
- current is split between the branches
- adding more resistors reduces the total resistance
what is the frequency of mains electricity
50hz
what is the UK mains voltage
230 V
what are the colours for each wire
neutral wire - blue
live wire - brown
earth wire - yellow and green
what does the earth wire do
safety feature - current will flow through this wire if there is a problem with the live or neutral wire to prevent current flowing through a person if they touch the object
what is a fuse
thin metal wire designed to melt or blow if the current exceeds a certain number of amps - 3,5,13
what are the stages of the national grid
power stations - produce high current , if this went straight into the grid, a huge amount of power/ energy would be lost as heat due to the resistance of the cables
step up transformer- increases voltage to 132kv which decreases the current
step down transformer - reduces the voltage to a safe 230V for homes and businesses
what happens when you touch a van de graaf generator
you become positively charged positive head repells positive hairs
how do you measure the volume of an irregular object
-measure mass of object
-fill eureka can up to the spout
- tie a string onto your object and submerge in the water in the eureka can, and wait for all the water to be displaced into the beaker
-pour water into measuring cylinder to measure the volume at eye level
what is internal energy
the sum of kinetic energy and potential energy
what is specific latent heat
the energy required to change the state of 1kg of a substance
what is gamma radiation
high energy EM wave that can be emitted by a nucleus due to a nucleus having excess energy
mass: 0
charge: 0
low ionising power
high penetrating ability
used for sterilisation
what is alpha decay
larger nuclei that ejects a helium nucleus (2 protons and 2 electrons) to become more stable.
mass : 4
charge : +2
high ionising power
low penetrating ability as it is absorbed by paper or a few cm of air
used for smoke detectors
