Question

Gelatins of three densities are poured into a large pan. Gelatin I is a diluted and soft gelatin, Gelatin II is a regular, firm gelatin, and Gelatin III is an extra firm, rubbery gelatin. A pulse in the shape of a crest is generated in III. A pulse (1/2 wavelength) is generated that extends exactly 1 color-band, that is, over 1 section of gelatin. In other words, the first pulse generated extends from the back end of the pan to the red/green boundary.

Choose whether the pulse will transmit as a trough or a crest under the following conditions.
At boundary B, the transmitted pulse will be a _______

Answer 1

When a pulse travels from a denser medium to a less dense medium, its characteristic (crest or trough) is typically maintained. Therefore, the transmitted pulse will remain a crest at boundary B between the different densities of gelatin.

Step-by-step explanation:

When a pulse travels through different densities of mediums, such as the gelatins with three densities described here, the characteristic of the pulse wave can change when it crosses from one medium into another. In this scenario, Gelatin III is an extra firm, rubbery gelatin and the pulse generated in it is a crest. As the pulse approaches the boundary of Gelatin II, which is a regular, firm gelatin and less dense than Gelatin III, the pulse will still transmit as a crest if it is moving from more dense to less dense medium.

However, if the boundary was such that the pulse was moving from a less dense to a more dense medium, the pulse could invert, meaning a crest would become a trough upon transmission. But based on the information provided, assuming the pulse moves from the extra firm (denser) Gelatin III to the less dense Gelatin II, the pulse will maintain its characteristic as a crest upon transmission at boundary B.