RP10 - Radiation and Absorption

Question 1

Outline the basic steps of the practical.

Answer 1

1. Place a Leslie cube on to a heatproof mat and fill with hot water
2. Use the infrared detector to measure the amount of radiation that is emitted from each side
3. Draw a suitable chart to compare the results for each surface

Question 2

What is a Leslie cube?

Answer 2

• A cube with different textured surfaces used to demonstrate the differing radiation emitted.
• Typically it has a matt white, a shiny silver/gold, a matt black and a shiny black side.

Question 3

Why is a heatproof mat used?

Answer 3

Boiling water is poured into the cube meaning the base can get hot and so a mat is used to protect the desk.

Question 4

What type of data is collected from this experiment?

Answer 4

The four different surfaces being measured produces categorical data.

Question 5

Give an example of a chart that may be used to display the data.

Answer 5

A bar chart with radiation intensity on the y-axis and the four surfaces on the x-axis.

Question 6

Which surface would you expect to emit the most radiation?

Answer 6

The matt black surface since good absorbers of radiation are also good emitters. Matt black surfaces are good emitters and poor reflectors.

Question 7

Which surfaces would you expect to emit the least radiation?

Answer 7

The shiny surfaces, as they are good reflectors and poor emitters.

Question 8

What type of radiation is being emitted?

Answer 8

Infrared radiation, which is part of the electromagnetic spectrum.

Question 9

What piece of apparatus is useful when filling the cube and why?

Answer 9

A funnel since the opening is very small and it will reduce the likelihood of spillages.

Question 10

What safety precaution should be taken when using a Leslie cube?

Answer 10

Avoid handling it with bare hands when filled with boiling water since the cube will be very hot.