# Help, AS level physics for a complete beginner

1. Jan 15, 2009

### I'mstuck...x

hello everyone, i'd be really appreciative of some help. i'm doing as physics and have never done proper physics before therefore i'm finding it quite hard. we are doing about waves at the moment and was wondering about a couple of things:-
1st - how to calculate frequency using the time base and a length? eg:- time base 2ms/cm length 5.4 cm, whats the frequency?
2nd - if y cm is the wavelength and Y-amplitude is a x amplitude how do i work out Vmax in volts? eg:- ycm = 5.6, Y-amplidude volt/cm = 5, what is Vmax volts?
3rd - what is the time base?
4th - how to work out the number of cycles using a graph?
Thankyou guys xxx

2. Jan 15, 2009

### mgb_phys

This is an osciloscope right?
The grid drawn on the screen are (usually) 1cm intervals

The timebase is how fast (ie how many cm/s) the beam sweeps across sideways.
So if two points are 1cm apart on the screen and the time base is 1ms/cm then the points are 1ms apart in time.

Similarly the vertical scale is in volts/cm so if a curve is 1cm high and the scale is set to 1cm/volt the signal is 1volt (note - in a real practical lab the probes you use have another factor of 10 included making it really 10v/cm)