The highest frequencies humans can hear is about 20000 Hz. What is the wavelength of sound in air at this frequency? The speed of sound is 340 m/s.

0.017 m

Explanation:

Wavelength: This can be defined as the distance covered in one complete oscillation by a wave. The S.I unit of wave length is meter (m).

The expression for wave length is given as

v = λf Equation 1

Where v = speed of sound in air, λ = wave length of sound, f = frequency of sound.

make λ the subject of the equation,

λ = v/f Equation 2

Given: v = 340 m/s, f = 20000 Hz

Substitute into equation 2

λ = 340/20000

λ = 0.017 m.

Hence the wave length of sound in air = 0.017 m

they are non-matter

explanation:

they are non-matter. basically, any type of energy or any abstract concept is an example of something that does not matter. other examples include dreams, magnetism, radio, and hate

the answer is neither ball has a charge.

because if they were both positively charged, they will repel each other.

if they were positively and negatively charged, they will seek.