Question

Which of the following physics knowledge statements is correct? ()
A. The essence of cathode rays and beta rays is electron flow, and their sources are the same
B. De Broglie pointed out that the greater the momentum of microscopic particles, the longer the corresponding wavelength
C. The greater the specific binding energy of the nucleus, the more firmly its nucleons are bound, and the more stable the nucleus
D. If a monochromatic light with a frequency greater than the limiting frequency of a metal is used to illuminate the metal, if the frequency of the incident light is increased, the number of photoelectrons escaping per unit time will definitely increase.

Answer 1

Answer: C.

Answer analysis:

A. β rays are high-speed electron streams, which are produced by β decay. In essence, a neutron in the nucleus becomes a proton and an electron. Cathode rays are also electron streams, which are produced by the ionization of electrons outside the nucleus. A is wrong;

B. From: λ=h/p, we can know that the greater the momentum of microscopic particles, the smaller the corresponding wavelength, so B is wrong;

C. The greater the specific binding energy of atoms, the more stable the nucleus, so C is correct;

D. The number of photoelectrons emitted per unit time has nothing to do with the frequency of photons, but is related to the intensity of light, so D is wrong.

So C is the correct answer.

Answer 2

What are cathode rays?

Cathode rays are electron streams formed by electrons emitted from the cathode of a low-voltage gas discharge tube under the acceleration of an electric field. It is essentially a high-speed electron stream with high energy and speed, usually reaching more than 10% of the speed of light. Cathode rays have two main properties: one is that they are perpendicular to the cathode, and the other is that they are negatively charged and always start from the cathode. This discovery is of great significance to the development of electronic science, and cathode ray tubes and other applications are also widely present in our daily lives, such as electronic oscilloscopes, television picture tubes, and electron microscopes.

Answer 3

About what beta rays are

Beta rays are high-speed electron streams released by radioactive nuclides during nuclear decay, also known as beta particles. The speed of these electrons can reach 99% of the speed of light, with strong penetrating power, but relatively weak ionization. When beta rays propagate in matter, they interact with atomic nuclei or extranuclear electrons, resulting in energy loss and scattering. Its penetrating power depends on the energy of the electrons, and it can usually penetrate aluminum plates several millimeters thick, but it may cause more serious harm in the body. Because beta particles are negatively charged, they are affected by forces in electric and magnetic fields, which changes their trajectory. In terms of protection, beta particles can be attenuated or blocked by external clothing, or completely blocked by a sheet of aluminum foil several millimeters thick.

The above information is for reference only. If you need a more detailed or professional introduction, it is recommended to consult relevant physics books or consult physics experts.

Answer 4

The metal limit frequency is an important parameter that describes the characteristics of the metal photoelectric effect. It refers to the minimum frequency of the incident light required to cause the metal to produce the photoelectric effect. 

When the frequency of the incident light is greater than this limit value, the electrons on the metal surface can absorb enough photon energy and escape from the metal surface to form a photocurrent. Different metals have different limit frequencies due to their different atomic structures and electronic arrangements. This characteristic has important application value in optoelectronics, materials science, and semiconductor technology. At the same time, the metal's limit frequency is also related to the highest frequency of its elastic vibration, which involves aspects such as the strength and fatigue performance of metal materials.

Answer 5

Microscopic particles refer to particles in the material world that are small in size but constitute the basic units of matter. These particles are more "wave-like" in the "wave-particle duality". For example, electrons, neutrons, protons, ions, molecules, etc. can all be regarded as microscopic particles. Scientists have gradually revealed the existence and properties of microscopic particles through long-term research and experiments.

Microscopic particles play a vital role in the composition of matter. They constitute the material world we are familiar with through different combinations and interactions. In particle physics, microscopic particles are divided into two categories: fermions and bosons. Fermions constitute the basic units of matter, while bosons are responsible for transmitting various interaction forces.

With the advancement of science and technology, human research on microscopic particles has continued to deepen, and new particles and phenomena have been discovered. These discoveries have not only promoted the development of physics, but also provided more clues for us to understand the mysteries of the universe. In the future, with the continuous improvement of experimental technology and the development of new experimental equipment, we have reason to believe that human understanding of microscopic particles will be more in-depth and comprehensive.

Answer 6

Louis Victor de Broglie, full name Louis Victor de Broglie, is a famous French theoretical physicist, the founder of wave mechanics, the creator of matter wave theory, and one of the founders of quantum mechanics. He was born in 1892 and received his doctorate from the University of Paris in 1924. 

He first proposed the concept of "matter wave" in his doctoral thesis. De Broglie's research revealed the profound connection between particles and waves and made important contributions to the development of quantum mechanics. He was awarded the 1929 Nobel Prize in Physics and was elected as an academician by many international academic institutions. 

De Broglie's research has had a profound impact on modern physics, and his contributions have been widely praised by later generations.

Answer 7

The frequency of incident light refers to the number of times a light wave vibrates per unit time, and is one of the important parameters for measuring the characteristics of light waves. Specifically, frequency determines the color and energy of light, as well as the way it interacts with other substances. According to the formula in physics, the frequency of incident light is inversely proportional to the wavelength of light, that is, the longer the wavelength, the lower the frequency; the shorter the wavelength, the higher the frequency. Light emitted by different light sources has different frequencies and wavelengths, and these characteristics have been widely studied and applied in spectroscopy. In physical phenomena such as the photoelectric effect, the frequency of incident light also plays a vital role, directly affecting the escape of electrons and the conversion of energy.

Answer 8

Binding energy refers to the energy released when two or more particles combine to form a larger particle, or the energy that the corresponding particles need to absorb when they decompose into the original particles. This energy reflects the tightness of the binding between particles.

At the atomic scale, the binding energy of atoms comes from the electromagnetic effect inside the atoms, and is the energy required to decompose atoms into electrons and nuclei.

At the nuclear scale, binding energy is the energy released when nucleons or nuclei form new nuclei, and it is also the energy required to decompose nuclei into free, unbound nucleons. The larger the binding energy value, the more stable the structure of the molecule (atom or nucleus). According to Einstein's mass-energy equation, binding energy can also be understood as the energy converted due to mass loss.

Answer 9

The nucleus is the core part of the atom, composed of protons and neutrons, of which protons are positively charged and neutrons are uncharged. 

The nucleus is extremely small, with a diameter between 10-15m and 10-14m. 

Its volume accounts for only a few hundred billionths of the volume of the atom, but it concentrates more than 99.96% of the mass of the atom, and its density is extremely high. 

It determines the mass and chemical properties of the atom and is an important field of atomic science research. 

In nuclear reactions, the fission or fusion of atomic nuclei can release huge amounts of energy, which is widely used in energy, medicine and other fields.