Physics

Article about the Electric field

On the subject of the electric charge, it was learned that like charges repel each other, while unlike charges attract each other. If a positively charged object is brought close to a negatively charged object, the two objects pull together so that they move toward each other. Conversely, if a positively charged object is brought close to a positively charged object, then the two objects repel each other so that they move away from each other. As studied on the subject of Coulomb’s law, electrically charged objects can accelerate other electrically charged objects because there is an electrical force acting between these electrically charged objects. The electric force that is exerted by an electrically charged object on other electrically charged objects is one example of a force that can act without contact. Another example of the force that can act at a distance is the force of gravity. The gravitational force is exerted by a mass object on the other mass objects.

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Article about Coulombs law

In the article about the electric charge and the types of electric charges explained that like charges repel each other while unlike charges attract each other. In other words, positively charged objects attract negatively charged objects, positively charged objects repel positively charged objects, and negatively charged objects repel negatively charged objects. This event shows the existence of the electrical forces acting on positively charged objects and negatively charged objects. What factors influence the electrical force between electrically charged objects?

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Article about The law of conservation of electric charges

Every material in the universe is composed of atoms. Atoms are composed of protons, neutrons, and electrons. Proton is positive electrically charged; electron is negative electrically charged, neutrons are not electrically charged. Inside the atom, there are some electrons, protons, and neutrons. If the number of electrons is equal to the number of protons, the total electrical charge on the atom is zero. Atoms like this are electrically neutral. If the number of electrons is more than the number of protons, then the atom becomes negative electrically charged. If the number of electrons is less than the number of protons, then the atom becomes positively electrically charged.

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Article about the Types of electric charge

Why does plastic repel plastic but attract glass? If you rub a plastic on dry hair and bring the plastic to the small pieces of paper, the plastic pulls the pieces of paper. Why can plastic also pull pieces of paper that were not rubbed with other objects? You will understand and can even explain the reasons for the phenomena experienced by the glass, plastic, pieces of paper or other objects as reviewed above after you learn the topic of electric charges and understand the reviews below.

Plastics that are rubbed with hair pulling glass rubbed with a cloth. Plastics and glass are attractive, so plastic and glass have different electrical charges. If an object repels plastic but pulls glass, it has a similar charge to the charge on the glass. Conversely, if an object repels a glass but pulls a plastic, it has a similar charge to the charge on the plastic.

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Article about the Electric charge in atoms

Please observe one of the objects that are around you. If you destroy an object, for example, it is a stone, the stone will be divided into smaller pieces. If the part of the stone is destroyed again, the stone pieces will turn into smaller pieces. What if the stone is destroyed again? Of course, the stone is smaller. Can stones be destroyed into smaller to infinite pieces? The reality shows that an object is divided into smaller ones will arrive at a point where the smallest part of the object cannot be divided into smaller ones. The smallest part of an object that cannot be divided is called an atom. So, atoms are the smallest part of every material in the universe.

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Article about the Optical instrument camera

Parts of camera

A simple camera consists of a convex lens, diaphragm, shutter, and film.

Convex lenses function to form the real and inverted image on the film. Unlike the lens of the eye that has a focal length that can change, the camera lens has a focal length that cannot change. The camera lens is a convex lens, not a concave lens because the image produced by the concave lens is always virtual. Instead, the image produced by a convex lens is real when the object distance is greater than the focal length. A real image is an image that exists because this image can be recorded on film. On the contrary, the virtual image is a false image so that the image cannot be recorded on film. The position of the real and inverted image produced by the convex lens coincides with the position of the film.

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Article about the Equation of astronomical telescope

Angle determines the size of an image of the object formed on the retina. As shown in the figure, the farther the object distance from the eye, the smaller the angle and therefore the smaller the image size formed on the retina.

The simple astronomical telescope has two convex lenses; each called the objective lens and the ocular lens. The objective lens has a greater distance from the eye, while the ocular lens has a distance closer to the eye. The objective lens functions to bring the image closer to the ocular lens, so the angle becomes larger. Ocular lens function to increase the angle so that the size of the image formed on the retina is greater.

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Definition of the astronomical telescope

Astronomical telescopes or astronomical binoculars are the optical instruments used to help the eye see celestial objects such as stars, planets, satellites, etc. Although the size of celestial objects is huge, the distance of celestial objects is so far that when observed using the eyes, celestial bodies appear small. Astronomical telescopes function to enlarge the image of celestial objects so that they can be seen using the eyes.

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Article about the Equation of microscope

Angle determines the size of the image of the object formed on the retina of the eye. As shown in the figure on the side, the smaller the size of the object, the lower the angle and hence the lower the size of the image formed on the retina. The small size of the image on the retina is the reason the eye is difficult to see small objects clearly, even though objects are viewed from a near point, a distance of 25 cm.

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Definition of microscope

A microscope is an optical instrument used to help the eye see minimal objects, where the tiny objects are difficult to observe directly using eyes or loupe.

There are two types of the microscopes, namely light microscope and electron microscope. This lesson discusses the light microscope, and the way it works about the topic of geometry optics includes refraction of light, the formation of images and the magnification of images of an object using a lens.

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