An oscilloscope displays the output from a small... | Physics (9-1) 0972 | Paper 2 Mock 01 | Multiple Choice (Extended)

Question 1 Report

An oscilloscope displays the output from a small hand-cranked generator. The time-base is set to 4 ms per division. The trace is shown below.

diagram

How many complete cycles appear in the first 8 divisions and what is the frequency of the output?

4 cycles, 250 Hz

2 cycles, 62.5 Hz

2 cycles, 125 Hz

3 cycles, 187 Hz

Answer Details

From the CRO trace, each complete wave (one full cycle) occupies 2 divisions on the screen.

The period \(T\) of the wave is:

\[T = 2 \times 4\,\text{ms/div} = 8\,\text{ms} = 0.008\,\text{s}\]

In the first 8 divisions, the number of complete cycles is:

\[\text{number of cycles} = \frac{8\,\text{div}}{2\,\text{div/cycle}} = 4\,\text{cycles}\]

The frequency is:

\[f = \frac{1}{T} = \frac{1}{0.008} = 125\,\text{Hz}\]

The correct answer is 4 complete cycles with a frequency of 125 Hz.

An oscilloscope displays the output from a small hand-cranked generator. The time-base is set to 4 ms per division. The trace is shown below. How many compl...