17 Now examine a pair of charged deflection plates see figur

1-7 Now examine a pair of charged deflection plates (see figure). The voltage difference between the plates is Vay. Assume the plates are separated by a istance d. Assume Vdy is positive. Draw an arrow to represent how the electric field should appear between the plates. Vd Volts &m.;.@ . \' 0. \'O_..#..\". coordinates Ed = ? 0Volts

Solution

Just a reminder of some basics:

• F=ma but also FE = qE

• W = -qV

• For parallel plates E = -V/d with d the distance between the plates.

• CRT = cathode ray tube

• When someone says “graph first thing vs. second thing” that means first thing on the yaxis and second thing on the x-axis (dependent variable vs. independent variable).

A cathode ray tube works by ‘boiling’ electrons off a cathode heating element and accelerating them with a large voltage difference. Then the high-speed electrons pass between a pair of charged deflection plates so that the path of the electron is altered. Finally, the electrons strike a screen coated with a fluorescent material and you see a scintillation take place. All of this is done in a vacuum so that the electron can travel through the CRT unhindered by collisions with air molecules. Actually, there are two pairs of deflection plates: a pair of charged deflection plates for vertical deflection and another pair of charged deflection plates for horizontal deflection.

The correct answer is in the range [10^6 , 10^7 ],