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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... 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 color of visible light that has the longest wavelength is red. The visible light spectrum shows that red light has wavelengths ranging from approximately 620 to 750 nanometers, longer than those of blue, green, and 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 relies on line-of-sight to function effectively; it emits infrared light that must directly reach the sensor on the television. If there is an obstacle, such as an armchair, the signal may be blocked, leading to failure in operation. In contrast, a radio wave remote control can transmit signals through obstacles, allowing it to function regardless of being blocked, which ensures that the television can be switched on from behind an armchair.