If the wavelength of sound and white light were to become equal, it would mean that the frequency of sound waves and the frequency of light waves are the same. However, this scenario is not possible in the context of our known physics, as sound waves and light waves operate in vastly different regions of the electromagnetic spectrum.
Sound waves are mechanical waves, which require a medium (such as air, water, or a solid) to propagate. They have relatively long wavelengths and frequencies ranging from a few Hertz to several kilohertz. On the other hand, white light is a combination of all visible colors of light and consists of a spectrum of wavelengths from approximately 400 to 700 nanometers (nm), corresponding to frequencies in the range of hundreds of terahertz (THz).
If, hypothetically, the wavelengths of sound and white light were to be equal, it would imply that the frequency of sound would need to be in the hundreds of THz range, which is far beyond the range of audibility for humans. Humans can typically hear sounds in the range of 20 Hz to 20 kHz, so any sound at such high frequencies would not be perceivable.
In conclusion, the scenario of sound and white light having equal wavelengths is not physically possible in our current understanding of the natural world. Therefore, it does not present any practical problems because it contradicts the fundamental properties of sound and light waves as we know them.