⚡ CHAPTER: ELECTRICITY (Class 10
Science)
1. Electric Current (I)
Definition: The rate of flow of electric charge through a conductor.
Q
I=
t
o I : Current (ampere, A)
o Q : Charge (coulomb, C)
o t : Time (seconds, s)
1 Ampere: When 1 coulomb of charge flows through a conductor in
1 second.
1 A=1 C /s
Direction of current: From positive → negative terminal
(conventional direction), though electrons move opposite.
2. Electric Potential and Potential Difference
Electric potential: Work done to move a unit positive charge from
infinity to a point in an electric field.
Potential difference (V): Work done per unit charge to move a
charge between two points.
W
V=
Q
o V : potential difference (volt, V)
o W : work done (joule, J)
o Q : charge (coulomb, C)
1 Volt: When 1 joule of work is done to move 1 coulomb of charge
between two points.
Device used: Voltmeter (connected in parallel).
3. Electric Circuit
, A closed path through which current flows.
Symbols used:
o Cell (—| |—)
o Battery (multiple cells)
o Resistor (zigzag line)
o Key/Switch, Ammeter, Voltmeter, etc.
Ammeter: Measures current (connected in series).
Voltmeter: Measures potential difference (connected in parallel).
4. Ohm’s Law
Statement: At constant temperature, the current flowing through a
conductor is directly proportional to the potential difference across
it.
V ∝ I ⇒ V =IR
o R : resistance of conductor (ohm, Ω)
Graph:
o V vs I is a straight line (for ohmic conductors).
o Slope = Resistance (R).
5. Resistance (R)
Definition: Property of a conductor that opposes the flow of
current.
l
R=ρ
A
o l : length of conductor
o A : area of cross-section
o ρ : resistivity of material
Dependence:
1. R ∝l (longer → more resistance)
Science)
1. Electric Current (I)
Definition: The rate of flow of electric charge through a conductor.
Q
I=
t
o I : Current (ampere, A)
o Q : Charge (coulomb, C)
o t : Time (seconds, s)
1 Ampere: When 1 coulomb of charge flows through a conductor in
1 second.
1 A=1 C /s
Direction of current: From positive → negative terminal
(conventional direction), though electrons move opposite.
2. Electric Potential and Potential Difference
Electric potential: Work done to move a unit positive charge from
infinity to a point in an electric field.
Potential difference (V): Work done per unit charge to move a
charge between two points.
W
V=
Q
o V : potential difference (volt, V)
o W : work done (joule, J)
o Q : charge (coulomb, C)
1 Volt: When 1 joule of work is done to move 1 coulomb of charge
between two points.
Device used: Voltmeter (connected in parallel).
3. Electric Circuit
, A closed path through which current flows.
Symbols used:
o Cell (—| |—)
o Battery (multiple cells)
o Resistor (zigzag line)
o Key/Switch, Ammeter, Voltmeter, etc.
Ammeter: Measures current (connected in series).
Voltmeter: Measures potential difference (connected in parallel).
4. Ohm’s Law
Statement: At constant temperature, the current flowing through a
conductor is directly proportional to the potential difference across
it.
V ∝ I ⇒ V =IR
o R : resistance of conductor (ohm, Ω)
Graph:
o V vs I is a straight line (for ohmic conductors).
o Slope = Resistance (R).
5. Resistance (R)
Definition: Property of a conductor that opposes the flow of
current.
l
R=ρ
A
o l : length of conductor
o A : area of cross-section
o ρ : resistivity of material
Dependence:
1. R ∝l (longer → more resistance)
