Flashcards in Physics Paper 1 GCSE Deck (126)
What is a system?
an object or group of objects
How can you calculate kinetic energy?
0.5 x mass x (speed)2
How can you calculate amount of elastic potential energy stored in a stretched spring?
0.5 x spring constant x (extension)2
How do you calculate gravitational potential energy?
mass x gravitational field strength x heaight
How do we calculate change in thermal energy?
mass x specific heat capacity x temperature change
What is the specific heat capacity of a substance?
amount of energy required to raise the temperature of one kilogram of the substance by one degree celsius
What is power?
rate at which energy is transferred or the rate at which work is done
How can you calculate power?
work done/ time
What is an energy transfer of 1 joule per second equal to?
power of 1 watt
How can energy be used?
transferred usefully, store or disspated
What can energy not be?
created or destoyed
The higher the thermal conductivity of a material the higher the rate of...
energy transfer by conduction across the material
How do we calculate efficiency?
useful output/total input
What are the main energy resources available of earth?
fossil fuels (coal, oil and gas)
What is a renewable energy resource?
One that is being replenished as it is used
What is a step up transformer used for?
increasing the voltage to several hundred thousand volts
reduce current and reduces energy lost by heating the wires
increase potential diffeence
What does a step down transformer do?
Reduce voltage down to several hundred volts to a safe level
What does the national grid consist of?
a system of transformers and high voltage cables
What is the big problem getting energy to homes?
Energy is always lost in the power cables. The bigger the distance between the power station and the homes the greater energy loss
Why do they increase the voltage to a high number in the step up transformer?
less energy is lost in the power cables at high voltage then at low voltages
What must a closed circuit include to allow an electrical charge to flow through it?
source of potential difference
What is the size of the electric current?
Rate of flow of electrical charge
How do you calculate charge flow?
current x time
What is the symbol for charge flow?
What does the current through a component depend on?
resistance of the component and potential difference across the component
The greate the resistance....
the smaller the current given potential difference across the component
How do you calculate potential difference?
current x resistance
The current through an ohmic conductor at a constant temperature is.....
directly proportional to the potential difference across the resistor
The resistance of components such as lamps, diodes, thermistors and LDRs is...