it is a physical entity which is Defined by excess or deficiency of electrons on body
Nota:
Define
s i unit- coulomb (C)
1 coulomb is equal to 6.25×10*18 electrons
charge on electron is equal to 1.6×10*-19 C
Properties
like charges repel each other comma while unlike charges attract each other
electric charges is conserved
electric charges exit in discreet package
electric charges are added algebraically (i.e. it is a scalar quantity)
Electric Current (I)
the rate of flowing charge through a conductor is as known electric current
s i unit Ampere (A)
I=Q/T
Ammeter instrument used to measure current. it is always connected in series. it should it should have you resistance, so that it does not change the value of current
Potential Difference (v)
the amount of work done in moving an unit positive charge from one point to another point of a conductor
electrostatic potential difference is the amount of work done in moving an unit positive charge from infinity to the given point
s i unit volt(V)
V=W/Q
∆V=V²-V¹=W/Q
Voltmeter instrument used to measure potential difference is known as voltmeter . it is always connected in parallel with resistors. it should have very high resistance so that it produce very less amount of current in a circuit
Electric Circuit
a continuous closed path at which a charge move. it consists of conducting wire , switch ,battery etc
it is of two type - (1) open circuit - when the current is not flowing in the circuit. (2) closed circuit - when the current flowing.
Ohm's Law
physical condition remaining constant , the current flowing through the conductor is directly proportional to the potential difference across the end of the conductor in the circuit
V≈I V=IR where ‘R’ is a constant called resistance
the conductor which obey Ohm's law a cold ohmic conductor
V-I graph
if V is plotted on y axis and I on the x-axis 10 slope of the graph (∆y/∆x)= R
if V is plotted on x axis and I on y axis comma then reciprocal of slope of graph {1/(∆y/∆x)} = R
Resistance (R)
it is the property of a material to oppose the flow of charge through it
s i unit ohm
R=V/I
some important terms related to resistance
resistor - a component in electric circuit which offers resistance to the flow of electron constituting electric current
variable resistance - a component used in electric circuit to change the current without changing the potential difference across the circuit
rheostat - it is a device used in electric circuit to change the resistance and hence current in the circuit
good conductor - material which offers low resistance to the flow of electrons or electric current in electric circuit
poor conductor - material which offers high resistance to the flow of electrons or electric current in electric circuit
insulator materials - which offers very high resistance to the flow of electrons or electric current in electric circuit