Question

How can the rate of emission of electrons in a cathode ray tube be increased?
A. Increasing resistance of filament
B. Increasing filament current
C. Decreasing filament current
D. Increasing magnetic field inside tube

Answer 1

To answer this question, we first need to understand what cathode ray tube. A vacuum tube that projects an electron beam onto a phosphor-coated screen to produce a bright spot at a position on the screen determined by the influence of a changeable magnetic field within the tube on the electron beam.

Complete answer:
Working of cathode ray tube: The mobility of electron beams is required for the CRT to function. The electron cannons produce electrons that are tightly concentrated and accelerated at high voltage. When a high-velocity electron beam collides with a fluorescent screen, it produces a light spot.

The beam passes via two pairs of electrostatic deflection plates after exiting the electron gun. Due to the applied voltage, these plates deflected the beams. The beam is moved upward by one set of plates, while the beam is moved from one side to the other by the other pair of plates. Because the electron's horizontal and vertical movement are independent of one another, the electron beam can be positioned wherever on the screen.

A CRT's functioning parts are encased in a vacuum glass envelope, allowing the emitted electron to freely flow from one end of the tube to the other. So, with this we conclude that, increase in the temperature of the cathode to increase the rate of electron emission, and increase the filament current to increase the temperature of the cathode.

So, the final answer is option B.

Note: One of the most dangerous pieces of equipment you'll repair is the CRT. Fortunately, you should only have to open a display and expose a CRT on rare occasions.However, given the dangers of working with CRTs, it's critical to understand what to do and what not to do when troubleshooting and servicing Macintosh systems with them.