Question

Cathode-ray-tube oscilloscopes have parallel metal plates inside them to deflect the electron beam. These plates are called the deflecting plates. Typically, they are squares 3.0 cm on a side and separated by 5.0 mm, with vacuum in between. What is the capacitance of these deflecting plates and hence of the oscilloscope? (Note:This capacitance can sometimes have an effect on the circuit you are trying to study and must be taken into consideration in your calculations.)

Short answer

thecapacitance of deflecting plates andoscilloscopeis

Step-by-step solution

About Cathode ray tube oscilloscopes 

A Cathode Ray Oscilloscope (CRO) is an instrument generally used in a laboratory to display, measure and analyse various waveforms of electrical circuits. A cathode ray oscilloscope is a very fast X-Y plotter that can display an input signal versus time or another signal.

Determine the capacitance of deflecting plates and oscilloscope

given the area A=

Required (0.030 of the deflecting plates and the separated distance between them is d We are asked to find the capacitance C of these deflecting plates_

The capacitance depends on the geometry of the capacitor; it is directly proportional to the area A of each plate and inversely proportional to their separation distance d and it is given by equation 242 in the form

Now We can plug our values for d, eo and A into equation (1) to get the capacitance in Farad where is the electric constant and equals(See Appendix F)

Therefore thecapacitance of deflecting plates andoscilloscopeis