$2$uestion $1$

Select the correct statement about the speeds of molecules as they vibrate in a material, at different temperatures.

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At a given temperature, all molecules have the same speed. This speed is larger for larger temperatures.

At a given temperature, the speeds of molecules have a distribution: some are smaller and some are higher. The average speed is larger for larger temperatures.

At a given temperature, some molecules are moving with a fixed speed. The rest remain in a crystalline state. At higher temperature the number of moving molecules is higher.

At a given temperature, the speeds of molecules have a distribution: some are smaller and some are higher. At higher temperatures the average speed is the same, but there is a larger variation in speeds.

At a given temperature, the speeds of molecules have a distribution: some are smaller and some are higher. At higher temperatures the average speed is the same, but there is a smaller variation in speeds.

Question $2$

$4$ pts