The document discusses Ohm's Law, which was developed by German physicist Georg Ohm. Ohm's Law states that the current through a conductor is directly proportional to the voltage applied, provided the temperature and other physical conditions remain constant. It can be expressed as V = IR, where V is voltage, I is current, and R is resistance. The document also provides examples of how to use Ohm's Law to calculate voltage, current, or resistance in circuits. It discusses the limitations of Ohm's Law and some objective practice questions related to its applications.

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Ohm’s Law
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 Georg Simon Ohm Alfred (1787-1854) devoted
Ohm’s Law.
 He was a German physicist and mathematician.
 As a high school teacher, he researched relationship
between voltage, current and resistance.
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3. Ohm’s Law
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Ohm’s Law states,
“The current flowing through a conductor is directly
proportional to the potential difference applied across its ends,
provided the temperature and other physical conditions remain
Constant”.
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4. Ohm’s Law
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𝑽 = 𝑰𝑹 𝐚𝐧𝐝 𝑰 𝜶 𝑽
𝑰 =
𝑽
𝑹
𝑹 =
𝑰
𝑽
𝑾𝒉𝒆𝒓𝒆,
𝑽 → 𝑷𝒐𝒕𝒆𝒏𝒕𝒊𝒂𝒍 𝑫𝒊𝒇𝒇𝒆𝒓𝒆𝒏𝒄𝒆
𝑰 → 𝑪𝒖𝒓𝒓𝒆𝒏𝒕
𝑹 → 𝑹𝒆𝒔𝒊𝒔𝒕𝒂𝒏𝒄𝒆
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5. Voltage and Current Relationship for Linear resistors
Ohm’s Law
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Voltage (V)
Current(I)
R
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6. Total Resistance
Ohm’s Law
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𝑺𝒆𝒓𝒊𝒆𝒔 𝑪𝒊𝒓𝒄𝒖𝒊𝒕: 𝑹 𝑻 = 𝑹 𝟏 + 𝑹 𝟐 + 𝑹 𝟑
𝑽 = 𝑽 𝟏 + 𝑽 𝟐 + 𝑽 𝟑
𝑰 = 𝑰 𝟏 = 𝑰 𝟐 = 𝑰 𝟑
𝑷𝒂𝒓𝒂𝒍𝒍𝒆𝒍 𝑪𝒊𝒓𝒄𝒖𝒊𝒕:
𝟏
𝑹 𝑻
=
𝟏
𝑹 𝟏
+
𝟏
𝑹 𝟐
+
𝟏
𝑹 𝟑
𝑽 = 𝑽 𝟏 = 𝑽 𝟐 = 𝑽 𝟑
𝑰 = 𝑰 𝟏 + 𝑰 𝟐 + 𝑰 𝟑

7.  Ohm also found that, in a network long wire have more
resistance than short wire and thin wires have more
resistance than fat wires.
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8.  Basic example of Ohm's law is your Electric Heater.
 In heater there is an high resistance in the path of current
then energy is wasted in the form of heat and that energy is
used to boil the water. That heater is nothing but your load
and there is no another load except resistance that's why it
produce heat.
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9. Ohm’s Law
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Limitations of Ohms Law:
 Ohm’s law is not applicable to unilateral networks. Unilateral
networks allow the current to flow in one direction.
 Ohm’s law cannot be applied to non metallic conductors.
 Ohm’s law cannot be applied without constant temperature.
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10. Ohm’s Law
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Limitations of Ohms Law:
 Ohm’s law is also not applicable to non – linear elements. Non-
linear elements are those which do not have current exactly
proportional to the applied voltage. That means the resistance
value of those elements changes for different values of voltage
and current. Such types of network consist elements like a
diode,transistor, Thyristors, Zener diode, Voltage regulators etc.
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11. Equivalent Law:
 Rowland / Hopkinson magnetic law is equivalent to
Ohm’s Law.
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12. Industrial Applications Base on Ohm’s Law:
 Ohm’s law can tell you how much wattage a circuit can handle.
This will helps circuit breaker dimension Analysis.
 Ohm’s law can also tell, if the system is robust enough to
handle the intended use.
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13. Objective Question – Ohm’s Law :
Ohm’s Law is termed as
1. Junction Law
2. Branch Law
3. Mesh Law
4. Node Law
Answer: 2
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14. Objective Question – Ohm’s Law :
A resistance of 10 𝛀 carries a current of 5 A. The
voltage developed across the resistor is.
1. 10 V
2. 40 V
3. 38 V
4. 50 V
Answer: 4
Ohm’s Law
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According to ohms law, V = IR = 5 x 10 = 50 V
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15. Objective Question – Ohm’s Law :
Which of the following is true for Ohm’s Law?
1. Voltage should remains constant
2. Temperature remains constant
3. Current remains constant
4. All of the above
Answer: 2
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16. Objective Question – Ohm’s Law :
A cell of EMF 6 V and resistance of 1 𝛀 is short
circuited. The current in the cell is.
1. 2 A
2. 4.6 A
3. 3 A
4. 6 A
Answer: 4
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According to ohms law, I = V / R = 6 / 1= 6 V
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17. Objective Question – Ohm’s Law :
The VI characteristics of Ohm’s Law gives.
1. Elliptical Curve
2. Parabola Curve
3. Straight Line
4. Hyperbola Curve
Answer: 3
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18. Objective Question – Ohm’s Law :
Two resistance R1 and R2 are connected in series across the voltage source
where R1 > R2. The largest voltage drop will be across.
1. R1
2. R2
3. Both R1 and R2
4. No Voltage drop
Answer: 1
Ohm’s Law
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Current same in series circuit and voltage is different.
Voltage drop, V = IR; V1 = IR1 and V2 = IR2
R1 > R2, So R1 have more voltage drop
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