Question

Which two notes are not an octave apart?1) 256 Hz and 512 Hz2) 262 Hz and 524 Hz3) 331 Hz and 622 Hz4) 277 Hz and 554 Hz

Answer 1

ANSWER

Option 3

EXPLANATION

Two notes are said to be an octave apart when the frequency of one note is exactly 2 times the other. In other words, it has twice as many waves.

Let us calculate the ratio of each option:

$\begin{gathered} \Rightarrow\frac{512}{256}=2 \\ \Rightarrow\frac{524}{262}=2 \\ \Rightarrow\frac{622}{331}=1.88 \\ \Rightarrow\frac{554}{277}=2 \end{gathered}$

As we can see, only in option 3 is the higher frequency not exactly 2 times the lower frequency.

Therefore, the answer is option 3.

Answer 2

ANSWER

Option 3

EXPLANATION

Two notes are said to be an octave apart when the frequency of one note is exactly 2 times the other. In other words, it has twice as many waves.

Let us calculate the ratio of each option:

$\begin{gathered} \Rightarrow\frac{512}{256}=2 \\ \Rightarrow\frac{524}{262}=2 \\ \Rightarrow\frac{622}{331}=1.88 \\ \Rightarrow\frac{554}{277}=2 \end{gathered}$

As we can see, only in option 3 is the higher frequency not exactly 2 times the lower frequency.

Therefore, the answer is option 3.