In a cathode ray tube, the number of electrons that reach the fluorescent screen is controlled by the
A. cathode.
B. deflecting plate.
C. anode.
D. grid.
?
The part of the atom that accounts for electricity is the
A. nucleus.
B. electron.
C. neutron.
D. proton.
B?
grid, electron.
To answer the first question, we need to understand how a cathode ray tube (CRT) works. A cathode ray tube is a device used in older TVs and computer monitors to display images. It consists of a vacuum-sealed glass tube with an electron gun at one end and a fluorescent screen at the other end.
The electron gun is responsible for generating and controlling a beam of electrons. When a voltage is applied to the cathode (A), it emits electrons through a process called thermionic emission. These emitted electrons then travel towards the anode (C) due to the difference in electric potential. As they pass through the anode, they gain kinetic energy.
To control the number of electrons that reach the fluorescent screen, we need a component that can modify or regulate the electron beam. The deflecting plate (B) and the grid (D) can both be used for this purpose. The deflecting plate is responsible for changing the direction of the electron beam, while the grid can control the intensity of the beam by applying a varying electric potential. However, neither the deflecting plate nor the grid primarily control the number of electrons that reach the fluorescent screen.
Therefore, the correct answer is A. cathode.
Moving on to the second question, we are asked about the part of the atom that accounts for electricity. To determine the answer, we should review the basic structure of an atom.
An atom consists of three main subatomic particles: protons, neutrons, and electrons. Protons (D) have a positive charge and are located in the nucleus (A) at the center of the atom. Neutrons (C) have no charge and are also found in the nucleus. Electrons (B) have a negative charge and orbit around the nucleus in specific energy levels.
When we talk about electricity, we are usually referring to the movement or flow of electrons. Electrons are responsible for carrying electric charge, and their movement constitutes electric current. Therefore, the correct answer is B. electron.