Answer:
Explanation:
Given
Length of each wire 
On wire A second harmonic frequency is given by

where f=frequency
v=velocity of wave
L=length of wire


For wire B third harmonic is given by



Answer:
Increase the amplitude
Explanation:
The energy conveyed by a wave is directly proportional to the square of its amplitude. Thus; E ∝ A²
This means that increasing the amplitude will lead to an increase in the energy.
Now, the amplitude of a wave is the height of a wave from it's highest point known as the peak, to the lowest point on the wave known as the trough whereas wavelength refers to the length of a wave from one peak to the next.
This means that increasing the amplitude has no effect on the wavelength.
Answer:
D
There is both a positive correlation and causation