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1. (a) Which colour of visible light has the longest wavelength? A blue B green C red D yellow (b) Some television remote controls use infrared radiation and other remote controls use radio waves - Edexcel - GCSE Physics Combined Science - Question 1 - 2019 - Paper 1
Question 1
1. (a) Which colour of visible light has the longest wavelength? A blue B green C red D yellow (b) Some television remote controls use infrared radiation an... show full transcript
Worked Solution & Example Answer:1. (a) Which colour of visible light has the longest wavelength? A blue B green C red D yellow (b) Some television remote controls use infrared radiation and other remote controls use radio waves - Edexcel - GCSE Physics Combined Science - Question 1 - 2019 - Paper 1
Step 1
Which colour of visible light has the longest wavelength?
Answer
The colour of visible light that has the longest wavelength is C red.
This can be explained by understanding the visible spectrum where red light lies on the far end, with wavelengths ranging from approximately 620 to 750 nanometers, making it the longest compared to other colours such as blue, green, and yellow.
Step 2
Explain why an infrared remote control may not switch on the television from behind an armchair but a radio wave remote control always will.
Answer
Infrared remote controls operate using infrared radiation which requires a direct line of sight between the remote control and the television. If an armchair obstructs this line of sight, the signal cannot reach the television, leading to a failure in operation.
Conversely, radio wave remote controls use radio frequencies which can penetrate obstacles such as furniture. This allows them to function effectively from behind an armchair, enabling control of the television without a direct line of sight.