A whale produces sound waves of frequency 5 Hz. The waves are detected by a microphone and displayed on an oscilloscope.

Question 9

A whale produces sound waves of frequency 5 Hz. The waves are detected by a microphone and displayed on an oscilloscope.

What is the time-base setting on the oscilloscope?

A 0.1 ms div^-1                  B 1 ms div^-1                      C 10 ms div^-1                   D 100 ms div^-1

Reference: Past Exam Paper – June 2015 Paper 11 Q4

Solution:

Answer: D.

Frequency f = 5 Hz

Period T = 1 / f = 1 /5 = 0.2 s

From the display, a period is represented by 2 divisions.

2 div - - - > 0.2 s or 200 ms

1 div - - - > 200 / 2 = 100 ms

So, the time-base setting on the oscilloscope is 100 ms div^-1