Quiz 15: Electric Forces and Electric Fields

Physics & Astronomy

A charged object can be defined as an object which has electric charge whether it is positive or negative. An atom in every neutral object consists of equal number of protons and neutrons. That means that if the net positive and negative charge is balanced, then the object is said to be in neutral. An unbalance between number of protons and electrons makes the object as positive or negatively charged object. Given that glass object is initially neutral. If the electrons are removed from the object, the net negative charge associated with the glass object decreases and hence the glass object becomes positively charged, that is, the glass object loses the electrons from it.

(a) The electrostatic interaction between two objects is described by Coulomb's law. This law states that the force of attraction or repulsion between two charges is directly proportional to the product of the magnitudes of the two charges and inversely proportional to the square of the distance between them. Mathematically it can be expressed as follows: img Here, img is the Coulomb's constant, img is the charge of the particle 1, img is the charge of the particle 2, and img is the distance between the two particles. Substitute img for img , img for img , img for img , and 1.80 m for r. img Therefore, the magnitude of force between two charges is img . (b) The charges given in the problem are of same king. As the both the charges are of same sign, they must experience a repulsive force.

An atom consists of positively charged protons inside the nucleus and negatively charged electrons revolve round the nucleus in various circular orbits. Protons inside the nucleus are bound together by nuclear forces. The electrons in the atom are bound with the nucleus through electric interaction. Since the nuclear forces are stronger than the electrostatic forces, electrons are more mobile than protons and are more easily removed from atoms than the protons