When you are rubbing the glass rod with the silk cloth, electrons are stripped away from the atoms in the glass and transferred to the silk cloth. This leaves the glass rod with more positive than negative charge, so you get a net positive charge.

When a nylon rod is rubbed with silk electrons are transferred from the rod to the silk, leaving the rod positively charged. When a rubber rod is rubbed with fur or felt electrons are transferred from the material to the rod, giving the rod a negative charge. Two negatively charged objects repel.

A glass rod becomes positively charged when rubbed with silk, while the silk becomes negatively charged. (a) The glass rod is attracted to the silk because their charges are opposite.

When a glass rod is rubbed with silk, it acquires a positive charge, means it is deficit of electrons i.e, electrons move from glass to silk. So glass rod becomes positively charged and silk rod is negatively charged.

The magnitude of the charge on each object is the same, and it is of opposite sign. What happens when two glass rods are rubbed with silk and they are brought close to each other? They repel each other.

When insulating materials rub against each other, they may become electrically charged . Electrons , which are negatively charged, may be ‘rubbed off’ one material and on to the other. The material that gains electrons becomes negatively charged. The material that loses electrons is left with a positive charge.

Two positively charged objects repel each other, and the ball moves away from the glass when they are held in each other’s proximity. Then the glass rod is rubbed with the wool, and the wool sheds electrons onto the glass, giving it a negative charge.

When a glass rod is rubbed with neutral silk, the glass becomes positively charged. The rubbing will strip the atoms of the rod of their electrons, which are negatively charged, leaving the rod to be positively charged. The silk will acquire these extra electrons, becoming negatively charged.

When a glass rod is rubbed with silk, glass rod loses electrons and silk gains electrons. Glass rod becomes positively charged and silk becomes negatively charged.

This includes most metals. Insulators, in contrast, are made from materials that lack conduction electrons; charge flows only with great difficulty, if at all. Even if excess charge is added to an insulating material, it cannot move, remaining indefinitely in place.

Some materials are better conductors than others and offer less resistance to the flow of charge. Silver is one of the best conductors but is never used in wires of household circuits due to its cost….Variables Affecting Electrical Resistance.

Resistivity and Temperature Coefficient at 20 C

Resistance can be both good and bad. If we are trying to transmit electricity efficiently from one place to another through a conductor, resistance is undesirable in the conductor. Resistance causes some of the electrical energy to turn into heat so some electrical energy is lost along the way.

Resistance is a measure of the opposition to current flow in an electrical circuit. Resistance is measured in ohms, symbolized by the Greek letter omega (Ω). Conductors: Materials that offer very little resistance where electrons can move easily.

If you are using such a resistor in a current-sensing application in a switch-mode circuit, you will get spurious readings or inaccurate behaviour. For a simple LED circuit there are no bad consequences of using a resistor of higher power.

Resistor Circuit Diagram We know that the function of resistance is to restrict the flow of current throughout the component. For example, if the rating of the battery is high, then we have to use the resistor with high resistance value. The resistance value can be measured using the formula Ohm’s Law.