The chart shows the speed at which light travels through different media.

\begin{tabular}{|l|c|}
\hline \multicolumn{1}{|c|}{Medium} & Speed of Light [tex]$(m/s)$[/tex] \\
\hline Water & [tex]$2.25 \times 10^8$[/tex] \\
\hline Air & [tex]$2.99 \times 10^8$[/tex] \\
\hline Glass & [tex]$1.97 \times 10^8$[/tex] \\
\hline Diamond & [tex]$1.24 \times 10^8$[/tex] \\
\hline
\end{tabular}

In which medium would light have the longest wavelength?

A. Water

B. Air

C. Glass

D. Diamond



Answer :

To determine in which medium light would have the longest wavelength, let's consider the relationship between the speed of light in a medium and wavelength. The speed of light [tex]\( c \)[/tex], frequency [tex]\( f \)[/tex], and wavelength [tex]\( \lambda \)[/tex] are related by the equation:

[tex]\[ c = f \cdot \lambda \][/tex]

When light travels through different media, its speed changes, but the frequency [tex]\( f \)[/tex] remains constant. Thus, the wavelength [tex]\( \lambda \)[/tex] is directly proportional to the speed of light [tex]\( c \)[/tex] in that medium:

[tex]\[ \lambda \propto c \][/tex]

This means that the medium with the highest speed of light will also have the longest wavelength.

Given the speeds of light in different media from the chart:

- Water: [tex]\(2.25 \times 10^8 \, m/s\)[/tex]
- Air: [tex]\(2.99 \times 10^8 \, m/s\)[/tex]
- Glass: [tex]\(1.97 \times 10^8 \, m/s\)[/tex]
- Diamond: [tex]\(1.24 \times 10^8 \, m/s\)[/tex]

We can observe that the speed of light is highest in air, at [tex]\(2.99 \times 10^8 \, m/s\)[/tex].

Therefore, the medium in which light would have the longest wavelength is air.