P1
- Created by: AlexMcNamee
- Created on: 23-04-16 16:58
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- P1abcd
- P1a) Heating Houses
- Energy always flows from a warmer body to a colder body
- A thermogram uses colour to show temperature
- When the temperature of a body increases, so does the average kinetic energy
- Temperature is measured on an arbitrary scale. Heat is measure on an absolute scale.
- Specific latent heat is the energy needed to melt or boil 1kg of the material.
- It is measured in J/kg
- Energy transferred = mass x SLH
- When a substance changes state, energy is needed to break the bonds that hold molecules together
- P1b) Keeping homes warm
- Double glazing reduces energy loss by conduction - the gap between two pieces of gas is filled with gas or contains a vacuum.
- Loft insulation reduces energy loss by conduction and convection
- Insulation blocks have shiny foil on both sides to reduce energy transfer by radiation
- density = mass x volume
- Energy can be transferred by conduction or convection
- Conduction is due to the transfer of kinetic energy, convection is when a gas expands when heated.
- Energy can be transferred by conduction or convection
- Energy efficiency is measured in Sankey diagrams
- Payback time = cost of insulation / annual saving
- Well instulated homes are energy efficient
- Everything that transfers energu will waste some energy as heat to surroundings
- P1c) A spectrum of waves
- Wave speed = frequency x wavelength
- The frequency order of waves is: Radio, Microwaves, Infrared, Visible, Ultraviolet, X-Ray, Gamma Ray
- Diffraction depends on the size of the gap, a larger gap means less diffraction.
- P1d) Lights and Lasers
- Signals sent are almost instant
- Each method has benefits and drawbacks
- Laser light differs from white light as it is only made up of a single frequency
- When the angle of refraction is 90, the AOI is called the critical angle
- An endoscope uses light to see inside the body
- Light passes alone optical fibres. The light is then reflected, which passes another set of fibres to an eyepiece or camera.
- If the AOI is bigger than the CA, the light is reflected; this is TIR
- An endoscope uses light to see inside the body
- Signals sent are almost instant
- P1a) Heating Houses
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