In this article, we will present the different consequences that can arise in the event of non compliance with the standards for the propagation of acoustics waves in their daily uses namely: sound system in our churches, evangelization campagn, refreshment bar, bistros, publics areas, etc. The acoustics waves are induced by vibration of mechanical surfaces which propagate to our ears translated by stamps. This is how we see that interactions between a vibrating body and the propagation medium obey the laws based on the existence of two forms of energy (propagated energy and that exchanged between the source and the propagation medium) described in this study. To better use acoustics waves, we will focus on the radiation impedance and the parameters allowing us to classify the sources of acoustics waves into two groups that we have called: omnidirectionnal and directionnal models.

During the publication of our article entitle «Study of the movement of a charged particle in electrodynamics »dans «International journal of Innovation and Applied studies», Vol 40, n°3, pp. 1007-1015, September 2023, we saw that a charged particle in motion is subject to two fields: the electric field E and the magnetic field B. Given the complexity of the research and experience, we preferred to first publish an article on the movement of a charged particle in a uniform electric field. Currently, we are going to publish an article on the movement of a charged particle in a uniform magnetic field (B) having tree major objectives, namely: knowing the Lorentz force, knowing precisely how a magnetic field constant B does not modify the cinetic energy of moving particle and finally to establish the characteristics of the movement of a charged particle in a uniform magnetic field. For the experiments, we will always use the laboratory of the National Pedagogic University (UPN) whose materials will be listed in the second paragraph (method and materials).

Today, users of radio frequencies face a double challenge, namely: - Respond to a growing need for communication channels (frequencies); - Maintain good quality of service (Qos). The difficulty results from the fact that the number of frequency (channels) available for radio electricity spectrum allocation is a very limited resource. This constraint imposes optimal and efficient use of frequencies, taking into account all the necessary parameters so as not to increase the probability of interference and also to avoid the malfunction of neigh boring stations. In the Democratic Republic of Congo in general and more particularly the city Province of Kinshasa, the Post and Telecommunications Regulatory Authority of Congo (ARTPC) has a limited number of usable frequencies in order to cover the needs of potential users.

In this article we will try to study the motion of a charged particle electro dynamic. Note that a moving charged particle finds its application in electronics, more precisely in television and the vacuum tube, thus giving rise to the different types of screen currently used to display an image of a transmitted object. Note that a moving charged particle is subject to two fields: the electric field □( (E ⃑ )) and the magnetic fiel□( (H ⃑ )) . This article will be the subject of a study in uniform electric field taking into account the physics laboratory reference of the department of physics and applied sciences of the National Pedagogical University. For this purpose, we used for our experiment: - Two metal plaques ; - An electron gun having a cathode et anode ; - A low and high voltage generator ; - A screen (flat surface for projecting light). The objective of this study is to establish the different equations of motion of a charged particle an uniform electric field E in a projection frame (O:i,j,k). To close the study, we will finally consider the electrical bending of a charged particle moving between two plaques having different potentials.

In this article, it is a question of studying the behavior of a band pass filter in BF and HF with passive elements. Said filter is widely used in electronics and telecommunications with many applications such as: manufacture and assembly of loudspeakers, limitations of working frequencies in a given interval according to its band, etc. We preferred to do this study based on mathematical and physical models which allowed us to discuss and interpret the different results obtained after simulation at the physics laboratory of the National Pedagogical University (UPN/RDCongo-Kinshasa) and which are presented as follows: In Low Frequency (BF): The capacitor blocked the signal and behaved like an open switch, on the other hand the coil allowed the signal to pass through. It acted as a closed switch. Therefore, the voltage at the filter output was zero; In High Frequency (HF): We had the opposite behavior in BF and the voltage at the output of the filter was always zero. The studied behavior led us to the determination of the band pass filter. The tool used for the simulation in Matlab, very powerful engineering software.

The modeling of an interconnecting network with optical fiber aimed to be represented by taking into account some phenomena (characters, forecasting, etc) with the help of mathematical equations or formula. In general way, the simulation of the later enables us to create a virtual laboratory with the help of Matrix Laboratory Software (Matlab) with the possibility of doing the tests at cheaper cost for the benefit of considerable time in relationship with the implementation of macroscopic trial at laboratory.