using oscilloscopes and geting voltages?

Question

an oscilloscope is used to make some basic electrical measurements the range knob settings are : veritcal 2 V/cm horizontal 5 msec/cm the trough to crest height of the sine wave is 7.4 cm the crest to crest length along te time axis is 4.8 cm

calulate the peak to peak voltage, the peak voltage, and the rms voltage

and also the period and frequency of the wave

Answer 1

Assuming that you are looking at a pure sine wave with no DC offset:
Vp-p = 7.4cm * 2V/cm = 14.8V
Vp = Vp-p/2 = 14.8V/2 = 7.4V
Vrms = Vp * 0.707 = 7.4V * 0.707 = 5.232V
FYI : 0.707=(sqrt2)/2

T = 4.8cm * 5ms/cm = 24ms
f = 1/T = 1/0.024s = 41.67hz