A PowerPoint Presentation on Current Electricity for grade 10 students. Submit feedback at wolfensteinpayne@gmail.com

1. Class X
Current Electricity
Optimal display in Microsoft PowerPoint (PPT File)

2. Current
Electricity
Circuit
Diagrams
Ohm’s Law
Charges and
Current
Voltage Resistance
Combination
of
Resistances
Factors of
Resistance
Heating
Effect
Joule’s Law
Electric
Power
Incandescent
Bulb’s
Brightness
Commercial
Unit of
Electricity

3. Electric Cell Battery (Group
of Cells)
Wire Joint Switch
Resistor Variable
Resistance
Ammeter Voltmeter
Circuit Diagrams

4. Definition of Charge (Q)
A fundamental property of matter creating an
external electrical field. Its SI Unit is Coulomb (C).
Classification
Charges can be positive or negative.
Properties
• Like Charges Repel
• Unlike Charges Attract
1C = Charge in 6.25 x 108
electrons
1 Electron = -1.6 x 10−19 Coulomb
Charges and Current

5. Even 1 Coulomb of Charge is huge and dangerous. It can exert a force of 9000000000N !
Did YOU KNOW?
Definition of Current (I)
The flow of charge in a conductor. Its SI Unit is Ampere (A).
How much is 1 Ampere?
1 coulomb of charge passing through a point in 1 second is
equivalent to 1 Ampere.
Charges and Current

6. 𝐼 =
𝑄
𝑡
=
𝑛𝑒
𝑡
1𝐴 =
𝑄
𝑡
=
1𝐶
1𝑆
1𝐴 = 103
𝑚𝐴 = 10𝜇𝐴
Where,
n = Number of Electrons
e = -1.6 x 10−19 C
s = Second
mA = milliampere
𝜇𝐴 = 𝑚𝑖𝑐𝑟𝑜𝑎𝑚𝑝𝑒𝑟𝑒

7. Measures only the magnitude of current. Measures the magnitude and direction of current.
A M M E T E R G A L V A N O M E T E R

8. + -
+ -
Electricity was discovered long before the discovery of electron. Current was then
considered the movement of positive charges from the positive terminal to the
negative terminal. This belief continues after the discovery of electrons too.
Conventional Current Actual Electronic Current
But we know that current actually is the movement of negative charges (electrons)
from the negative terminal to the positive terminal.
Direction of Current

9. Electrons in a conductor move randomly
around their atoms but this does not
create current.
To create current , many electrons need
to move in a unidirectional* path. This can
be achieved by providing some energy to
the electrons to move in a specified
direction.
We call this energy ‘Voltage’ or ‘Potential
Difference’.
*For DC Current only
Voltage

10. *For DC Current only
Definition of Voltage (V)
Voltage or Potential Difference is an electromotive force
that creates and maintains electric current in a circuit.
How do we measure Voltage?
Voltage is measured in Volts with a device called the
Voltmeter.
How much is 1 Volt?
The amount of work done to move 1 coulomb of charge
between two points.
𝑉𝑜𝑙𝑡𝑎𝑔𝑒 =
𝑊𝑜𝑟𝑘 𝐷𝑜𝑛𝑒
𝐶ℎ𝑎𝑟𝑔𝑒
=
1𝐽𝑜𝑢𝑙𝑒
1 𝐶𝑜𝑢𝑙𝑜𝑚𝑏
= 1 𝑉𝑜𝑙𝑡
Voltage

11. Measures potential difference across two points.
Creates potential difference across the terminals of
a circuit.
V O L T M E T E R C E L L / B A T T E R Y

13. According to Ohm’s Law :
V ∝ I
V = 𝐼𝑅
Ohm’s Law
The electric current flowing through a Conductor is directly proportional
to the voltage applied across its ends, provided that the physical
conditions (such as temperature) remain unchanged.
V = Voltage, I = Current
R = Constant of Proportionality
0,0
1,3
2,6
3,9
4,12
5,15
0
2
4
6
8
10
12
14
16
0 2 4 6
Voltage
(V)
Current (A)

14. Definition of Resistance (R)
The property of a conductor that slows down or
resists current flowing in a conductor.
How much is 1 Ohm (Ω) ?
If 1 volt produces a current of 1 Ampere, then it is
said to be a conductor having a resistance of 1 Ω.
Rheostat
It is a device that can provide variable resistance in
a circuit.
Resistance

15. Factors of Resistance
N A T U R E O F
M A T E R I A L
L E N G T H O F
C O N D U C T O R
A R E A O F
C O N D U C T O R
𝝆 ∝ 𝑅 L ∝ 𝑅 A ∝ 1/𝑅
Temperature is included in the nature of material (𝜌). A = 𝜋𝑟2
𝑹 =

16. Resistivity is the resistance of a conductor of 1m length and 1𝑚2
cross sectional
area. It is also known as Specific Resistance.
Conductors Resistivity (𝛀𝒎)
Silver 1.60 x 10-19
Copper 1.62 x 10–8
Aluminium 2.63 x 10-8
Tungsten 5.20 x 10-8
Nickel 6.84 x 10-8
Iron 10.0 x 10-8
Chromium 12.9 x 10-8
Mercury 94.0 x 10-8
Manganese 1.84 x 10-6
Alloys Resistivity (𝛀𝒎)
Constantan 49 x 10-6
Manganin 44 x 10-6
Nichrome 100 x 10-6
Insulators Resistivity (𝛀𝒎)
Glass 1010 – 1014
Hard Rubber 1013 – 1016
Ebonite 1015-1017
Diamond 1012-1013
Paper (Dry) 1012
Resistivity

17. –
+
In Series Circuits, Current (Volume of Water
flow) remains the same but Voltage
(Water Pressure) changes at every
component of the circuit.
= devices or bulbs
Series Circuit Analogy
Electric Circuit Water Pipeline
Electrons Water
Voltage Water Pressure
Current Water Flow
Bulbs or Other Devices Filters, hose, taps etc.

18. In Parallel Circuits, Current (Volume of
Water flow) changes at each new path
of the circuit but Voltage (Water
Pressure) remains constant.
= devices or bulbs
Parallel Circuit Analogy
Electric Circuit Water Pipeline
Electrons Water
Voltage Water Pressure
Current Water Flow
Bulbs or Other Devices Filters, hose, taps etc.

19. 1
𝑅𝑇𝑜𝑡𝑎𝑙
=
1
𝑅1
+
1
𝑅2
+
1
𝑅3
+
1
𝑅4
+ ⋯ +
1
𝑅𝑛
Reciprocal of Total Resistance = Sum of the
reciprocals of all the individual resistances.
𝑅𝑇𝑜𝑡𝑎𝑙 = 𝑅1 + 𝑅2 + 𝑅3 + 𝑅4 + …. + 𝑅𝑛
Total Resistance = Sum of the individual
Resistances
Combination of
Resistances
R E S I S T O R S I N
S E R I E S
R E S I S T O R S I N
P A R A L L E L
𝑅1
𝑅2
𝑅2
𝑅1

20. According to Joule’s Law of Heating:
H ∝ 𝐼2
H = 𝐼2
𝑅𝑇
Joule’s Law
When an electric current passes through a conductor, heat H is
produced, which is directly proportional to the resistance R of the
conductor, the time t for which the current flows, and to the square of
the magnitude of current I.

21. Heater Microwave Oven Incandescent Bulb Electric Fuse
Heating Effects of
Electric Current
Practical Application of Heating Effect of Electric Current
• Room heaters, Hair Dryers
• Microwave Ovens
• Filaments of Incandescent Bulbs
• Electric Fuses etc.

22. Electric Power
We know, Power is the rate of energy consumption.
𝑃 =
𝐸
𝑇
=
𝑉𝑄
𝑇
= 𝑉𝐼 = 𝐼2
𝑅𝑇 =
𝑉2
𝑅
and, 𝐸 = 𝑃𝑇
Where,
P = Power, E = Energy, T = Time, V = Voltage, Q = Charge,
I = Current
KWh is a
commercial
energy unit
used in
Electricity Bills.

23. A Bulb with a given power, like 20W actually tells its power rating, which means that
for a given constant Voltage, the bulb consumes energy at 20W. That constant in
India is 220V. In series connection, the bulb with the lowest power rating is the
brightest whereas, in parallel connections, the bulb with the highest power rating is
the brightest.

24. 𝑄 = 𝑛𝑒 𝑊 = 𝑉𝑄
𝐼 =
𝑄
𝑇
𝑉 = 𝐼𝑅 𝑅 = 𝜌
𝑙
𝑎
𝑅𝑆𝑒𝑟𝑖𝑒𝑠 = 𝑅1 + 𝑅2 + …. + 𝑅𝑛 𝑅𝑃𝑎𝑟𝑎𝑙𝑙𝑒𝑙 = =
1
𝑅1
+
1
𝑅2
+ ⋯ +
1
𝑅𝑛
P = 𝑉𝐼 P = 𝐼2
𝑅 P = 𝑉2
/𝑅
𝐸 = 𝐼2
𝑅𝑇 = 𝐻
𝑃𝑃𝑎𝑟𝑎𝑙𝑙𝑒𝑙 = 𝑃1 + 𝑃2 + ⋯ + 𝑃𝑛 𝑃𝑆𝑒𝑟𝑖𝑒𝑠 =
1
𝑃1
+
1
𝑃2
+ … +
1
𝑃𝑛
𝐸 = 𝑃𝑇
𝜌 = 𝑅
𝑎
𝑙

25. Thank you!
DRD, X/C, 13
c