Copper, because it has the lowest specific electrical resistance.
specific electrical resistance aka volume resistivity is a fundamental property of a material that quantifies how strongly that material opposes the flow of electric current. A low resistivity indicates a material that readily allows the flow of electric current.
Answer:
70 m.
Explanation:
Given,
Frequency, f = 20 HZ
speed of sound, v = 1400 m/s
wavelength of the waves = ?
we know,
v = f λ



Hence, the wavelength of the wave is equal to 70 m.