12th Physics Chapter 2 – 2 Mark Questions (Important & Repeated – TN Board)
Prepare for exams with 12th Physics Chapter 2 (Current Electricity) important 2 mark questions. This collection includes most repeated and previously asked questions based on TN Board exams, helping students revise key concepts quickly and score better.
Current Electricity – 2 Mark Questions
Most Repeated 2 Marks
1.State kirchoff’s voltage rule?
It states that in a closed circuit the algebraic sum of the products of the current and resistance of each part of the circuit is equal to the total emf included the circuit.
This rule follows from the law of conservation of energy for an isolated system.
2.State Kirchoff’s Current rule?
Kirchhoff’s current rule states that the algebraic sum of the currents at any junction of a circuit is zero. It is a statement of law of conservation of electric charge.
3.What is peltier effect?
When an electric current is passed through a circuit of a thermocouple, heat is evolved at one junction and absorbed at the other junction. This is known as peltier effect.
4.What is Seebeck effect?
Seebeck discovered that in a closed circuit consisting of two dissimilar metals, when the junctions are maintained at different temperatures an emf (potential difference) is developed. The current that flows due to the emf developed is called thermoelectric current.
5.Distinguish between drift velocity and mobility?
6.State joule’s law of heating
It states that the heat developed in an electrical circuit due to the flow of current varies directly as
- H = I2RT
- The square of the current
- The resistance of the circuit and
- The time of flow.
7.Define Resistivity or electrical resistivity?
Electrical resistivity of a material is defined as the resistance offered to current flow by a conductor of unit length having unit area of cross section.
Its unit is ohm-metre Ωm
8.Define temperature coefficient of resistance?
It is defined as the ratio of increase in resistivity per degree rise in temperature to its resistivity at T
Appeared Once 2 Marks
1.Why current is a scalar?
Current has both magnitude and direction. But the direction of current does not obey vector laws of addition. So, current is a scalar quantity.
2.State microscopic form of ohm’s law?
- J is the current density,
- E is the Electric Field,
- σ is the conductivity.
3.What is Thomson effect?
If two points in a conductor are at different temperatures, the density of electrons at these points will differ and as a result the potential
difference is created between these points.
Thomson effect is also reversible.
4.State macroscopic form of ohm’s law?
- Macroscopic form of Ohm’s law can be stated as “the potential difference across a given conductor is directly proportional to the current passing throught it when the temperature remains constant”.
- V = IR
