Energy Flashcards
Efficiency equasions
Efficiency= useful energy(x100)/ total energy
What factors affect the rate of energy transfer?
The material the object is in contact with
The objects shape
The objects surface area
The temperature difference between the object and it’s surroundings
Non renewable sources
Coal Oil Wood Gas (natural) Nuclear
Renewable sources
Wind Solar Wave Tidal Hydroelectric Geothermal
The temperature rise when an object is heated depend on…
The amount of energy supplied
The mass of the substance
What the substance is
How do you find the Specific heat capacity of a metal?
C=e/mx0 E is energy transferred M is the mass C is the specific heat capacity 0 is the temperature
What forms of insulation may you have?
Loft insulation>fibreglass
Cavity walls
Aluminium foil>behind radiators
Double glazed windows
What is a u-value?
U values tell us how much energy passes through 1m2 of materials per second when the temperature difference across it Is 1 degree.
Heating water at home is expensive what else can you do?
Install solar panels which doesn’t use fuel to heat the water but are expensive
List the 5 types of energy
Chemical Electrical Gravitational potential Kinetic Elastic potential
Energy cannot…
Be created or destroyed
What is a heat sink and how does it protect electrical components?
A heat sink is a metal panel which when put on a electrical appliance conducts heat away from the appliance so it can cool or not get too hot.
How does loft insulation reduce energy transfer?
Stops the heat escaping through your roof using fibreglass by reducing conduction
How do cavity walls prevent energy transfer?
They trap air as it passes through one wall enclosing and keeping the heat in. They also reduce conduction and convection.
How does double glazing reduce energy transfer?
If heat passes through the glass it is trapped in the vacuum which keeps the heat in and also reduces conduction and convection
How does aluminium foil reduce energy transfer?
It reflects the heat back into the room
What are solar panels used for?
The solar energy heats water and they are placed on the roof that faces south.
Describe the particles in a solid
The particles are held next to each other in fixed positions. They vibrate about their fixed positions so the solid keeps it’s shape.
Describe the particle structure of a liquid
The particles in a liquid move about at random and are in contact with each other. This means a liquid doesn’t have its own shape and can flow.
Describe the particles in a gas
They move randomly and are very far apart. This means the density of a gas is much less. In general the particles is a gas tend to have more energy that those in a solid.
The rate of temperature change of a substance when it is heated depends on….
The mass
The energy transferred
Specific heat capacity
The greater the mass of an object the It’s temperature increases when heated.
Fill in gap
Slower
What is the specific heat capacity?
The energy needed to increase the temperature of 1kg of a substance by 1 degree
How can you calculate how much energy is required to raise the temperature of an object?
E=mxcx°
Energy=massxSHCxtemperaturerise
