Which occurs when a wave is reflected? the wave’s frequency increases. the wave’s amplitude increases. the wave can speed up. the wave can flip upside down.

The wave can flip upside down.

Reflection is the bending of a wave when it cannot pass through. For example, plain mirrors which are flat, a ray of light hits the mirror and is reflected from the mirror since it cannot pass through  

When reflection occurs the speed and frequency of the wave does not change but the wave is flipped upside down.

The speed does not change because speed is affected by the change in medium the frequency also remains the same since the energy of the wave does not change.

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.