Culomb's LAW

Q. ) What kind of charges are produced on each, when
(i) a glass rod is rubbed with silk and
(ii) an ebonite rod is rubbed with wool ?

Ans. (i) On glass rod : positive charge and on silk : negative charge.
(ii)On ebonite rod : negative charge and on wool : positive charge.

Q. ) An ebonite rod held in hand can be charged by rubbing with flannel but a copper rod cannot be charged like this. Why ?

Ans. Both the human body and the copper rod conduct electricity. When it is attempted to charge a copper rod by rubbing, the charge flows from the rod to the earth through the hand. However, when ebonite rod is charged by rubbing, the charges so produced stay on the ebonite rod, as it is bad conductor of electricity.

Q. ) What does q1+q2=0 signify in electrostatics ?

Ans. The charges q1 and q2 are equal and opposite;

Q. ) When a polythene piece is rubbed with wool, it acquires negative charge. Is there a transfer of mass from wool to polythene ?

Ans. The polythene piece acquires negative charge due to transfer of electrons from wool it. Since electrons are material particles, there is a transfer of mass from wool to polythene.

Q. ) A glass rod, when rubbed with silk cloth, acquires a charge 1.6 x 10-13 coulomb. What is the charge on the silk cloth ?

Ans. Silk cloth will also acquire a charge 1.6 x 10-13 coulomb. However, it will be negative in nature.

Q. ) What is the value of charge on electron ? Is a charge less than this value possible ?

Ans. Charge of electron, e=1.6 x 10-19C A charge less then e is not possibe. In fact, a charged body can posses charge equal to +ne or -ne, where n is an integer.

Q .) What do you mean by quantisation of charge ?
What is the least possible value of charge ?

Ans. A positively charged particle can posses positive charge equal to the charge on a proton (+1.6 x 10-19C ) and a negatively charged particle equal to the charge on an electron (1.6 x 10-19C). A particle can not have a fractional part of this elementary amount of charge i.e. 1.6 x 10-19C .

Q .) What is the basic cause of quantisation of charge ?

Ans. During the charging process, on integral number of electrons is transferred from one body to the other. Therefore, charge possessed by a body is always an integral multiple of +ne or -ne1.6 x 10-19C.


Coming Subjects