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8 (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 - Question 8 - 2019 - Paper 1
Question 8
8 (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:8 (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 - Question 8 - 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. In the visible spectrum, red light has wavelengths that range from approximately 620 to 750 nm, which are longer than those of blue, green, or yellow light.
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
An infrared remote control uses infrared light to send signals, which requires a direct line of sight. If you are behind an armchair, the infrared signal may be blocked, preventing it from reaching the television. In contrast, a radio wave remote control uses radio waves that can penetrate obstacles and do not require direct line of sight, allowing it to work from behind furniture.