Your brother is insisting that you'll never hear a sound produced behind a barrier wall at the end of your yard. you notice that the door within the wall is open and quickly explain to him that the sound will be able to reach you due to
a. reverberation
b. diffusion
c. focusing
d. diffraction

Correct answer choice is :

D) Diffraction

Explanation:

Diffraction relates to several aspects that happen when a wave meets a barrier or a slit. It is described as the bending of waves around the edges of a barrier or gap into the area of the geometrical darkness of the barrier. Diffraction is created by one wave of light being turned by a diffracting thing. This shift will make the wave to have a collision with itself. The powerful examples of diffraction happen in waves where the wavelength is close to the mass of the object creating diffraction.

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it

c. magnitude and direction