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Figure 5 shows a tuning fork - Edexcel - GCSE Physics Combined Science - Question 3 - 2018 - Paper 1
Question 3
Figure 5 shows a tuning fork. When the prongs of the tuning fork are struck, the prongs vibrate in the directions shown by the arrows on Figure 5. Describe how the... show full transcript
Worked Solution & Example Answer:Figure 5 shows a tuning fork - Edexcel - GCSE Physics Combined Science - Question 3 - 2018 - Paper 1
Step 1
Describe how the vibrating tuning fork causes a sound wave to travel through the air.
Answer
When the prongs of the tuning fork are struck, they vibrate or oscillate. This vibration creates areas of compression and rarefaction in the surrounding air. The prongs move in the same direction as the sound wave travels, causing the air particles to oscillate back and forth. This motion transfers kinetic energy to adjacent air molecules, allowing the sound wave to propagate through the air. It is important to note that sound waves are longitudinal.
Step 6
Explain, in terms of speed, why the light behaves like this.
Answer
The colours of light represent different wavelengths, which travel at different speeds. When light crosses from air into glass, the change in medium causes the light to refract, bending as it moves into a medium where it travels slower. Since different wavelengths bend by different amounts, this leads to the dispersion of light into the colours of the spectrum.