P1 Energy Flashcards
What is the law of energy?
Energy cannot be created or destroyed it can only be stored or transferred.
Give the eight energy stores.
1) Thermal energy
2) Kinetic energy
3) Gravitational potential energy
4) Elastic potential energy
5) Chemical energy
6) Magnetic energy
7) Electrostatic energy
8) Nuclear energy
Give the four transfers of energy and when they are done.
1) Mechanically (when a force is doing work).
2) Electrically (work done by moving charges).
3) Heating
4) Radiation (light and sound)
What is a system?
A system is a single object or group of objects performing a certain task.
What is a closed system?
A system where neither matter nor energy can enter or leave.
What is the transfer of energy in the system of water boiling in a kettle?
Energy is transferred electrically to the thermal energy store of the kettle’s heating element, which transfers energy by heating to the water’s thermal energy store.
Work done is just another way of saying (blank)
Energy transfered.
Give the equation for Kinetic energy, say what each symbol stands for and the units for each thing.
E=1/2 x m x v^2
E= Kinetic Energy which is measured in joules (J)
m= mass which is measured in kilograms (kg)
v= velocity which is measured in meters per second (m/s)
Give the equation for Gravitational Potential energy, say what each symbol stands for and the units used to measure each thing.
E=m x g x h
m= mass measured in kilograms (kg)
g= Gravitational field strength (N/kg)
h= height which is measured in meters (m)
What is an example of a process that would result in energy being gained in an objects kinetic energy store.
Any movement on an object for example the movement of a body part of vehicle.
What is an example of a process that would result in energy being gained in an objects Gravitational potential energy store.
The lifting/raising of an object in a gravitational field off the ground.
What is an example of a process that would result in energy being gained in an objects Elastic potential energy store.
The stretching or squashing of an object.
Give the equation for the change in thermal energy, what each symbol means and the units to measure each thing in the equation.
ΔE=m x c x Δθ
ΔE= change in thermal energy which is measured in (
Give the equation for the change in thermal energy, what each symbol means and the units to measure each thing in the equation.
ΔE=m x c x Δθ
ΔE= change in thermal energy which is measured in (J)
m= mass which is measured in Kilograms (kg)
Δθ= temperature change which is measured in degrees Celsius
Define specific heat capacity
The amount of energy needed to heat 1 kg of a substance by 1 degrees.
What is the specific heat capacity of water.
4200 J/kg (degrees Celsius)
Give the 5 stages of the Specific heat capacity required practical.
1) Get a block of a solid material with two holes in it.
2) Measured the mass of the block then wrap in an insulating layer to reduce energy transferred to the surroundings. Insert the thermometer and heater.
3) Measure the initial temperature of the block and set the volts of the power supply to 10V. Turn on the power supply and start a stopwatch.
4) As the block heats up take readings of the temperature from the thermometer and current from the ammeter in the circuit every minute for 10 minutes. You should find that the current through the circuit does not change as the block heats up.
5) When you’ve collected enough readings turn off the power supply. Use -P= V x I- to calculate the how much energy has been transferred to the heater. To calculate how much energy has been transferred to the heater at each temperature reading using the formulae E= P x t where t is time in seconds since the experiment began.
Define the term dissipated
It is when some energy is not transferred usefully into the store you want it to go.
Describe the energy transfer of a closed system (a flask filled with soup) when a cold spoon is placed in it. The lid is still sealed.
Energy is transferred from the thermal energy store of the soup to the useless thermal energy store of the spoon.
What is power?
Power is the rate of energy transfer, or the rate of doing work.
What is power measured in and what does this equal?
Power is measured in watts. 1 W= 1 Joule of energy transferred per second.
Give the equation for power, state what each symbol represents and what the unit is for each thing.
P= E/T P= Power, measured in watts (W) E= Energy transferred, measured in joules (J) T= Time, measured in seconds (s)
Give the conservation of energy principle.
- Energy can be transferred, stored or dissipate but it can never be created or destroyed. `
What is conduction?
- Conduction is the process where vibrating particles transfer energy to neighboring particles.
