Q. ) What kind of charges are produced on each,
Ans. (i) On glass rod : positive charge and
on silk : negative charge.
(i) a glass rod is rubbed with silk and
(ii) an ebonite rod is rubbed with wool ?
(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 ?
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 .
What is the least possible value of charge ?
Q .) What is the basic cause of quantisation of
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.