1. What is static electricity?
Static electricity means electricity at rest. If we join
a charged conductor to another
conductor, electricity flows from one to the other. This
way an electric current is
produced, which lasts for a moment only. Static
electricity is no use. Rubbing of two
different materials having different electrons produces
this.
2. What is current?
Flow of electrons in any conductor is called electric
current. Its symbol is ‘I’ and
measuring unit is Ampere measured by ammeter or ampere
meter.
3. What is electro-motive force (emf) or voltage?
It is the pressure that moves the electrons to flow in
any conductor. It is also known
as electromotive force voltage. Its symbol is ‘E’ or ‘V’
and measuring unit is volt
measured by voltmeter.
4. What is potential difference (P.D)?
The difference of potential between two points in a
circuit is the voltage required to
drive the current between them or the voltage drop
between those two points is
called the potential difference.
P.D = R * I volts.
5. What is terminal voltage (VT)?
It is the voltage available at the terminal of the source
of supply. It’s symbol is VT.
VT = emf – P.D
6. What is resistance?
Resistance is the property of a substance, which gives
opposition to flow of electrons
through itself. Its measuring unit is ohm and measured by
ohmmeter, multi meter,
wheat stone bridge, and post office box. There are two
types of resistances and they
are fixed resistance and variable resistance.
7. What is ampere?
The international ampere is defined as that steady
current which, flowing through a
solution of silver nitrate, deposits silver at the rate
of 0.001118 gm/sec.
8. What is volt?
The international volt is defined as 1/1.0183 of the emf
of a Weston cadmium cell. It
is that difference of potential which, when applied to a
conductor whose resistance is
1 (one) international ohm, will cause a current of 1
(one) international ampere to
flow.