Friday, May 8, 2009

1. E L E C T R O S T A T I C S .3M ANSWERS,

1. E L E C T R O S T A T I C S .3M ANSWERS
1. WHY IS IT SAFER TO SIT INSIDE A BUS THAN STANDING UNDER A TREE?
During a thunder accompanied by lightning, it is safer to sit inside a bus than in open ground or under a tree. The metal body of the bus provides electrostatic shielding, where the electric field is zero.During lightning the electric discharge passes through the body of the bus.
2. DEFINE ELECTROSTATIC INDUCTION
It is possible to obtain charges without any contact with another
charge. They are known as induced charges and the phenomenon of
producing induced charges is known as electrostatic induction. It is
used in electrostatic machines like Van de Graaff generator and
capacitors.
3. DEFINE CAPACITANCE OF A CONDUCTOR.
The capacitance of a conductor is defined as the ratio of the
charge given to the conductor to the potential developed in the
conductor. C = q /V : unit=farad.
4. DEFINE : FARAD.
The unit of capacitance is farad. A conductor has a capacitance
of one farad, if a charge of 1 coulomb given to it, rises its potential by
1 volt. The practical units of capacitance are μF and pF.
5. WHAT ARE DIELECTRICS?
A dielectric is an insulating material in which all the electrons are
tightly bound to the nucleus of the atom. There are no free electrons
to carry current. Ebonite, mica and oil are few examples of dielectrics.

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