Question

Two musical notes that have a frequency ratio of 2:1 are said to be separated by an octave. A musical note that is separated by an octave from C(128 Hz) has a frequency of (a) 345 Hz (b) 256 Hz (c) 512 Hz (d) 68 Hz

Answer 1

(b) 256 Hz

Step-by-step explanation:

a ratio 2:1 or 2/1 means that the higher tone has twice (2 times) the frequency of the lower tone.

so,

2 × 128 = 256 Hz

of course, the octave could also go down. but the same ratio must apply. again, the higher frequency must be twice the lower frequency.

so, the frequency of an octave down of the given tone would then have to be

128/2 = 64 Hz

but this is not a given option.

so, 256 Hz is the only correct answer option.