Types of charges and their interaction - class-VIII

Copper rod cannot be charged easily by friction because it is a conductor. Only non-conducting materials can be charged easily by friction.

When body losses electrons, it becomes electron deficient and acquires positive charge.

When body gains electrons it gets negatively charged.

Electroscope is a device that is used for detection and identification of charges on objects.

When two bodies are rubbed on one another, they acquire charges equal in amount and opposite in nature.

Same charges repel while opposites charges attract each other when placed together.

In the process of rubbing objects with one another, both acquire small electric charges. These objects are called charged objects.

When refill is rubbed on polythene it acquires small electric charges. Due to presence of these charges, pieces of paper gets attracted.

When any of these materials are rubbed together, the one in higher order gets positive charge (+) and the one in the lower order gets negative charge (-). The correct frictional order is: glass, wool, ebonite and plastic.

By convention, glass acquire higher order than silk as losses electron. So, on rubbing, glass acquires positive charge and silk acquires negative charge.

Plastic comes below fur in the frictional series of electric charges. So, fur will get positive charge and plastic rod will get the negative charge.

When two bodies are rubbed for charging, the one acquiring positive charge comes first, on a higher position, in electrostatic series. From the series, it may be interpreted that if two objects are rubbed with each other, the one coming higher in the series will acquire positive charge and the other coming lower in the series will acquire negative charge.

For most of the materials, if those are rubbed with materials occurring higher in electrostatic series, will acquire negative charge. And if those materials are rubbed with materials occurring lower in electrostatic series, will acquire positive charge. Dry human skin, occurring at top of the electrostatic series will always acquire positive charge. Teflon, occurring at the bottom of the electrostatic series will always acquire negative charge.

When the forearm is rubbed with a cloth of silk, the dry forearm acquires positive charge. So, all the hairs there acquire same positive charge and repel each other. Thus the hairs stand straight after rubbing.

Static charges are generated by rubbing or friction.

When rubbed with silk, glass and plastic acquire opposite charges. So, the glass rod and the plastic straw, after being rubbed by silk, will attract each other.

The balloons will be seen to repel each other as both are charged with same polarity.

Both of them, refill as well as polythene, gets charged by friction.

Static electricity, while combing dry hair, is generated by friction between comb and dry hair.

Moving charges constitute electric current.

When rubbed by wool, glass becomes positive and rubber becomes negative. Opposite charges attract. So, the balloon and the glass tumbler will attract each other.