8K sci Flashcards
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what is internal energy
The Energy stored in the movement of particles
what are Energy measured in
Joules (J)
What is Temperature
Something that describes how hot or cold an object is
What is Temperature Usually measured in
Degrees Celsius (°C)
Are internal energy and temperature the same and why
No, because the temperature is measurable using thermometers, but the internal energy something contained cannot
what are the 3 factors the amount of internal energy in something depends on
Temperature
Material
Mass
How does the Energy flow
from hotter objects to a cooler one
The bigger the difference in temperature the ____ the energy is transferred
Faster
what happens to cold and hot objects (During energy transfer)
cold objects become hotter and vice versa until they are both same temperature
what happens to particles when a liquid Evaporates
the fastest moving particles in a liquid escape forming gas the particles that are left store less energy as movement so the temperature of the remaining liquid is lower
what are the 4 ways energy can be transferred by heating
Evaporation
Radiation
Conduction
Convection
how is energy transferred through radiation and what state could this happen through
Energy is transferred through radiation via electromagnetic waves This type of energy transfer doesn’t require a medium and can happen in all states of matter
how is energy transferred through Conduction and what state could this happen through
Energy is transferred through conduction within all 3 states when one particle gains energy it passes it to surrounding particles through collisions.
how is energy transferred through Convection and what state could this happen through
Energy is transferred through convection by the movement of the fluids due to temperature differences. Warm fluid rises, and cooler fluid sinks, creating a cycle.
2 ways to insulate the cold in houses
Double Glazed Windows
Dark coloured coating
2 ways to insulate the heat in houses
light coloured coating
windows
give an example insulator
wood
give an example conductor
metal
define Accuracy
close to the true value of the thing being measured
define Precision
several measurement results are close together
define Random Errors
Errors formed due to factors that are difficult to control
define Systematic Errors
all results from the instrument are incorrect by a similar amount
how could you avoid Systematic Errors
Adjust instruments and use proper measurement techniques.
how could you avoid Random errors
Take multiple measurements and average the results.
define power
the amount of energy transferred per second
what are the 2 units power is measured in
watts (W)
Kilowatts (KW)
how many Watts are there in a Kilowatts
1000W=1KW
1 Watts = how many joules transferred per second
1 watt = 1 Joule transferred every second
Define Efficiency
The amount of useful energy transferred compared with the total amount supplied
what is a Sankey diagram and how could we interpret it
by looking at the width of each arrow representing its proportion
what is the Equation for Efficiency
Efficiency = Useful energy transferred/total energy supplied x100%
what unit is used by companies for your Utilities fees and what it means
Kilowatt-hour(kwh) the amount of energy transferred in 1 hour by an appliance with a power of 1KW
what is the Equation for kilowatt-hour
Power rating (KW) x time (hour) = Energy use (kwh)
define Payback time and its Equation
Payback time is the period it takes for an investment to recover its initial cost through profits or savings. Payback time = cost of change/saving per year
