NCERT 12th Class Physics Ohm’s Law and Resistance
Ohm’s Law
Ohm’s law: It states that “the current flowing through a conductor is directly proportional to potential difference between the ends of the conductor provided physical conditions like temperature, pressure etc. remain the same”.
i.e. VαI
or V = IR
Here V is apotential difference,I is current and R is Resistance of the conductor.
Resistance: It is the ability of a conductor to oppose the flow of electric current.
SI unit of resistance is ohm.
Factors on which resistance of a conductor depends:
- Nature of the material of the conductor
- Length of the conductor ‘l’
- Area of cross-section ‘A’
- Temperature
ie R ∝l
R ∝ 1/A
R= 𝜌l/A
Where 𝜌 is resistivity of the material of the conductor.
What to study the same topic in Hindi? click on Physics in Hindi
The resistivity of thematerial of a conductor:
𝜌=RA/l
If we have A=1m2 and l=1m
So 𝜌=R
The resistivity of the material of a conductor is defined as the resistance of the conductor having unit length and unit area of cross section. S.I. unit is ohm-meter (Ω – m).
For the practice of Current Electricity problems & more, Click on NCERT Physics Class 12.
Ohmic conductors: Ohmic conductors are the conductors which obey ohms law and for which V-I graph is linear.Eg: Metallic conductor.
Click on Physics notes Class 12 for notes on various chapters and NCERT Solutions.
For more doubts, CBSE mock tests, CBSE exam study material,online sample papers, register with TakshilaLearning.
Comments
Post a Comment
Thank you we will contact ASAP.