K.C.S.E Physics Q & A - MODEL 2013PP2QN017

K.C.S.E Physics Q & A - MODEL 2013PP2QN017

(a) Figure 9 shows a cathode ray tube in which a beam of electrons is cast on the screen.

​(i) state how the electrons are produced in the tube. 
(ii) state how the electron beam is detected. 
(iii) State the reason for having a variable potential difference (p.d.) at the:
(I) grid; 
(II) anodes. 
(b) Figure 10 shows the waveform of a signal applied at the y-plates of an oscilloscope whose time-base is switched to the scale of 2 milliseconds per centimeter.

​Determine:
(i) the period of the signal; 
(ii) the frequency of the signal. 

ANSWERS

(a) (I) Thermionically by cathode 
(ii) causing fluorescence on screen 
(iii) (i) control brightness of fluorescence 
(ii) to focus the electron beam