The question asks about the phenomenon responsible for creating images on old television screens, which are cathode ray tubes (CRTs). This involves the interaction of electrons with a screen coated with special materials.
A) Fluorescence — When the electron beam strikes the fluorescent/phosphorescent coating on the screen, the material absorbs the energy and immediately re-emits it as visible light, creating the picture. This rapid emission and decay of light are characteristic of fluorescence, which is essential for displaying moving images without significant ghosting.
The question asks to identify the particles that constitute cathode rays. This is a fundamental concept in atomic structure and the history of physics, specifically related to J.J. Thomson's experiments.
C) Electrons — Cathode rays are indeed streams of negatively charged particles called electrons. This was definitively established by J.J. Thomson's experiments.
The question asks about the fundamental building blocks of matter. To answer this, we need to recall the basic structure of matter and its constituent particles.
Correct Option: D) Atoms are the basic units of matter. Electrons, along with protons and neutrons, are the fundamental subatomic particles that constitute every atom. Therefore, electrons are basic constituents of all atoms.
Identify the RIGHT statements from the following
a) Thomson argued that the amount of deviation of the particles from their path in the presence of electrical or magnetic field depends upon the following reasons.
b) The magnitude of the negative charge on the particle, greater the magnitude of the charge on the particle, greater is the interaction with the electric or magnetic field and thus greater is the deflection
c) The mass of the particle — lighter the particle, greater the deflection.
d) the strength of the electrical or magnetic field — the deflection of electrons from its original path increases with the increase in the voltage across the electrodes, or the strength of the magnetic field
The question asks to identify the correct statements regarding J.J. Thomson's experiment on the deflection of cathode rays (electrons) in electric and magnetic fields. Thomson's experiment was crucial in determining the charge-to-mass ratio of the electron. The deflection of a charged particle in an electric or magnetic field depends on several factors, which are described in the statements.
B) All a,b,c,d — All the statements correctly describe the factors influencing the deflection of charged particles in electric and magnetic fields, which were fundamental to J.J. Thomson's work on the electron.
What is the charge of electron? (in C)
The question asks for the charge of an electron in Coulombs (C). This is a fundamental constant in physics and chemistry that candidates appearing for competitive exams are expected to know.
Correct Option: A) The charge of an electron is \(-1.6 \times 10^{-19}\) C. This is the internationally accepted value for the elementary charge, with a negative sign indicating the electron's charge.
The question asks about the discovery of positively charged particles resulting from an electrical discharge in a modified cathode ray tube. This refers to a historical experiment crucial for understanding atomic structure.
C) Canal rays. Electrical discharge carried out in a modified cathode ray tube (with a perforated cathode) led to the discovery of canal rays, which are streams of positively charged particles (ions).