GCSE Questions - Electromagnetic Spectrum
Q10. The diagram shows the electromagnetic spectrum.
(a) Tick the correct statement relating to the direction of the arrow in the above diagram.
| The wavelength decreases and the wave speed in air increases. |
|
| The frequency increases and the wavelength increases. |
|
| The frequency increases and the wave speed in air stays the same. |
 |
| The wavelength increases and the wave speed in air increases |
|
[1 mark]
(b) Explain how the properties of X-rays make them suitable for the medical imaging of bones.
X-rays pass through soft tissue (skin/muscle/etc)but are absorbed by bone.
[2 marks]
(c) Bobby investigated the infrared radiation emitted from the sides of a hollow metal box cube.
The sides of the cube are different colours or textures.
The diagram below shows the equipment used.
Boiling water was poured into the cube. The amount of infrared radiation emitted from each vertical surface was then measured.
The table shows the results:
Type of surface |
Temperature in °C |
Matt black |
68.0 |
Matt white |
65.5 |
Shiny black |
66.3 |
Shiny silver |
28.0 |
(i) Boiling water is a hazard in this investigation. Suggest how the risk of harm could be reduced in this investigation.
complete the investigation standing up
use (slightly) cooler water (NOT cold water)
do not touch the hot cube
[1 mark]
(ii) What is the control variable in this investigation?
The control variable is the distance between each side of the cube and the infrared detector.
[1 mark]
(iii) The four temperature values in the results table cannot be used to show that the infrared detector gives precise readings. Give the reason why.
The measurements for each surface have not been repeated. If precise the repeated values would cluster closely.
[1 mark]
(iv) Bobby looked at the data in his table and concluded:
'A black surface always emits more infrared radiation than a white surface.'
Explain how using an infrared detector with a resolution of 1 °C would have affected his conclusion.
Bobby could not conclude that black surfaces always emit more infrared than white surfaces as the reading for the matt white and shiny black would both be 66 °C
[2 marks]
(d) Albedo is a measure of the amount of solar radiation reflected by an object compared to the total solar radiation incident on the object.
A 'perfect reflector' has an Albedo value of 1.0
A 'perfect absorber' has an Albedo value of 0.0
(i) What is the Albedo value of a perfect black body?
0.0
[1 mark]
(ii) The diagram shows two points, A and B, just above the Earth's surface.
The average Albedo value of the Earth's surface is 0.3
The Albedo value of thick cloud varies between 0.6 and 0.9
At night the air at point A cools faster than the air at point B.
Explain why.
At night, more radiation is emitted from the Earth than absorbed from space.
Cloud cover reflects radiation back towards the Earth at night. So at B some of the radiation will be reflected back, but at A there is no cloud cover so a larger proportion of the radiation will be emitted into space.
[3 marks]
(Total 12 marks)
About this site
If you just say 'pass through tissue' it is insufficient to get you the mark - you have to say 'soft tissue'. X-rays are used to find 'lumps' of dense tissue (breast X-rays).
