Morse code is essentially the same as binary. That is, there are two "digits", a dot or a dash.
There are 26 letters in the English alphabet. Clearly, we can't just use one dot or dash, since that could only encode 2 letters at the most. We can't use two symbols because that could only encode 4 letters at the most. Similarly, 3 symbols means [tex]2^3=8[/tex] letters at most.
We have to select the smallest power of 2 that exceeds or is equal to 26. In this case, [tex]2^5=32>26[/tex], so we would have to use up to 5 symbols to encode each letter in the alphabet.
