Answer:

Explanation:
Velocity of wave in stretched string is given by the formula

here we know that
T = 4 N
also we know that linear mass density is given as

so we have

now the tension in the string is double
so the velocity is given as


Answer:
The solution is given in the picture attached below
Explanation:
Answer:
The boundaries cause the waves to change direction an effect called <u>refraction.</u>
Explanation:
When a wave crosses a boundary between different materials, the speed of the wave and its wavelength changes.When passing from air to water the two properties (speed and wavelength) decreases, and the wave is observed to change direction as it crosses the boundary between the two material.The bending of the wave is called refraction.
Explanation:
Below is an attachment containing the solution.