<u>Answers
</u>
1) B. longitudinal.
2) B. air is cooler than the ground.
<u>Explanation
</u>
Q1
There are two categories of a wave. That is transverse and longitudinal waves. Transverse waves forms crests and troughs while longitudinal forms compressions and rarefaction as they travel. Rarefactions are regions where the wavelengths are longer than other regions.
Q2
As the ray of light moves from an optically less dense to a more dense region it bends towards the normal.
If the sound is bending away from the earth's surface, then the ground must be warmer than the air. As the sound travels it moves from optically dense medium to a less dense medium. For this reason it bends away from the normal. This can only happen when, B. air is cooler than the ground.
The formula for ethane is C2H6. (the 2 and 6 are supposed to be subscripts) they show the number of atoms per element. So there are two carbon atoms and six hydrogen atoms in ethane. The subscript in a chemical formula represents the amount of that atom in that compound's formula. <span>In chemistry, no subscript indicates 1 of that particular atom. HCl contains 1 atom of hydrogen and 1 atom of chlorine, whereas H20 contains 2 atoms of hydrogen and 1 atom of oxygen.It should be noted, however that this does not necessarily hold true for empiracle formulas, since these have been reduced to the simplest whole number ratio and do not necessarily reflect the number of each element present in an actual molecule.
I hope this helps you! Good luck :)</span>
The accurate description of vibrations is that, neither ultrasonic nor infrasonic vibrations can be heard by humans. The Infrasonic vibration frequency is lower than 20Hz, whereas ultrasonic vibration frequency is greater than 20,000Hz. The normal range of frequency of hearing for humans is only 20Hz-20,000Hz.
