Question

waves move fastest in
low-temperature gases.
low-temperature solids.
high-temperature gases.
high-temperature solids.

Explanation:

To determine where waves move fastest, we recall the properties of wave propagation:

1. Medium Type (State of Matter): Waves (especially mechanical waves like sound) travel fastest in solids because the particles in solids are closely packed, allowing quicker transfer of energy. In gases, particles are far apart, so wave speed is slower.
2. Temperature Effect: Higher temperature increases the kinetic energy of particles, making them vibrate more vigorously. In solids, higher temperature means particles have more energy to transfer wave energy, increasing wave speed.

Comparing the options:

• Low - temperature gases: Slow (low temp + gas state).
• Low - temperature solids: Slower than high - temp solids (lower particle energy).
• High - temperature gases: Faster than low - temp gases but still slower than solids (gas particles are far apart).
• High - temperature solids: Particles are closely packed (solid state) and have high kinetic energy (high temp), so wave energy transfers fastest here.

Answer:

D. high - temperature solids (assuming the options are labeled A, B, C, D as: A. low - temperature gases, B. low - temperature solids, C. high - temperature gases, D. high - temperature solids)