P7- Infrared Radiation

Question 1

What is infrared radiation?

Answer 1

Part of the electromagnetic spectrum, along with visible light. It has a longer wavelength than visible light waves.

Question 2

Key points on infrared radiation:

Answer 2

• The higher the temperature of an object, the more infrared radiation it emits in a given time.
• An object that has a constant temperature emits radiation across a continuous range of wavelengths.
• Black body radiation is radiation emitted by a body that absorbs all the radiation.

Question 3

Factors that affect the temperature on earth from the rate of infrared radiation that is -

Answer 3

• Reflected back into space
• Absorbed by the earths surface and atmosphere
• Emitted from the earths surface back into space.

Question 4

How is global warming affected by radiation?

Answer 4

-Some gases in the atmosphere absorb longer wavelengths of infrared, stopping it leaving the earth. This radiation is then emitted back to the earths surface.

Question 5

What type of surfaces are better at absorbing or reflecting infrared

Answer 5

• Dull Matt dark surfaces are better absorbers.

- Light shiny surfaces are better reflectors

Question 6

Why does the moons temperature vary so greatly

Answer 6

-It doesn’t have an atmosphere, so it is unable to block out or trap in infrared radiation.

Question 7

What is heat?

Answer 7

-The amount of energy stored in an object or substance
Or
-The amount of energy transferred from one object to another.

Question 8

What is temperature?

Answer 8

-The measure of how hot or cold something is due to energy stored or transferred to an object.

Question 9

What is infrared radiation?

Answer 9

-A type of electromagnetic wave which transfers heat energy.

Question 10

What is thermal imaging?

Answer 10

• When an infrared camera detects heat emissions from an object and produces an image.
• Yellow/orange means high levels of infrared.

Question 11

What is the unit for specific heat capacity?

Answer 11

J/kg degrees C

Question 12

What is the equation for specific heat capacity?

Answer 12

Number of joules of heat / mass (kg) X temp change

Question 13

How does Wall cavity and loft insulation insulate the home?

Answer 13

• Insulation materials are poor conductors of heat, therefore reducing heat loss by conduction.
• They also prevent air circulation inside the cavity, reducing heat loss by confection.