Later people encountered many other phenomena and in the process of making a new hypothesis they had a constraint that it has to be consistent with the old theory and the assumption of the existence of lines of force coming in or out from a particular charged particle whose direction is associated to the nature of the particle and is seemed to serve the purpose. We are pretty sure that is true from the numerous experiments done. Here comes my concern, we know that the lines of force emerge from the charged particles but what is the cause for the emergence of lines in the first place? I agree that it is fundamental to assume such a thing to exist but can t this be investigated further? Isn t it a valid question? After all fundamental assumption is also called a belief but an acceptable belief. The reason for giving it such a status of being acceptable is that it is helping us understand the other phenomena. But we don t know the cause for such a belief or what exists beyond that belief. The fundamental assumptions or the accepted beliefs are the points where we stop thinking about anything because when we accept something we won t find any need to think about it. It must not be the case, we must reason or investigate the existence of anything, of course only from the knowledge we acquired, then we will find the cause for it and only then it will lead us to the ultimate truth.
Where does charge come from?
We know that all objects are made up of and atoms are composed of smaller particles called protons, electrons and neutrons. Protons and neutrons are found in the nucleus of an atom and eletrons are found in an area outside often described as an electron cloud (see for more advanced description). Remember that the hydrogen atom is only composed of a a single proton and electron. It does not contain a neutron. Both protons and electrons have a basic property called charge. This property is not like other physical properties of matter. Charge however can be measured and it affects the behavior of particles. The amount or magnitude of charge on protons is the same as electrons. The protons are positively charged, the electrons are negatively charged, and the neutrons are neutral. The terms positive charge and negative charge were originally described by Benjamin Franklin. Charges exert Force A is defined as a push or pull. Charged particles exhibit similar behaviors of push and full. A force that pulls particles together is called an attractive force.
So electrons are attracted to protons and this is what holds together. A force that pushes apart particles is a repulsive force. Force of attraction exists between oppositely charged particles – electrons and protons are therefore attracted to each other. Similar charges will repel so negative electrons repel each other. The simple rule for electric charges is: Like chages repel each other and unlike charges attract each other. What is an Electric Field? The concept of an electric field is used to explain why charged particles exert forces on each other. When an electron moves into the electric field of a proton it is pulled to the proton. The electric field gets stronger as we approach the particle. Electric fields are visualized by drawing extended lines as show in the image below. Note that for positive charge the field lines point outward and for negative field they point inward. Electric Field lines between a positive and negative charge are shown below. As above the lines are drawn toward the negative charge. What is an Electroscope and What is it Used For? An electroscope is a scientific instrument that is used to detect the presence and magnitude of electric charge on a body.
It was the electrical measuring instrument. A typical classroom electroscope consists of a metal knob at top and a metal rod with thin metal leaves at the bottom. The rod is inserted into a flask with a rubber stopper (see image below). In an uncharged electroscope the leaves hang straight down. When a negatively charge object such as a negatively charged glass rod touches the knob the electric charge travels down the tube to the metal leaves. since both leaves now contain negative charges they will repel. Similarly if the knob is touch with a positively charged rod electrons will be drawn up the metal rod leaving positively charged leaves. The leaves again will repel. Test your Understanding: 2. Objects that have the same charge will 3. Protons are 1000x more massive than electrons. This means b) the mass does not does not affect the magnitude of charge, protons and electrons have the same magnitude of charge 4. A force is defined as 5. Which statement is true for electric field force lines a) positive force field lines are drawn outward, negative lines are drawn inward b) negative field lines are drawn outward, positive lines are drawn inward