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CBSE CLASS XII

Kirchhoff's Law

A : Following questions are very short answer type. They are to be answered in one or two sentences. They may carry one mark each.

1. State any one of Kirchhoff's Laws

B : The following questions are of short answer type. Each of them may carry 2 or 3 marks.

1. State Kirchhoff’s Law. ? Derive the condition for obtaining balance in Wheat Stone Bridge
2. State and explain Kirchhoff’s Law.
3. Using the Kirchhoff’s Law in the given circuit, evaluate the values of current I₁, I₂ and I₃.

4. Two cells of EMF 6 V and 12 V and internal resistances 1 ohm and 2 ohms respectively are connected in parallel so as to send current in the same direction through an external resistance of 15 ohms.
   (i) Draw the circuit diagram and
   (ii) using Kirchhoff’s Law calculate
         (a) current through each branch of the circuit and
          (b) p.d. across the 15 ohms resistance.
5. By applying Kirchhoff’s laws, calculate the current flowing through each resistance in the network shown in this diagram.



Using Kirchhoff’s Law determine the current I1, I2 and I3 for the network shown below:

6. Two cells of emfs 1.5 V and 2.0 V and internal resistances 2 ohms and 1 ohm respectively have their negative terminals joined by wire of 6 ohms and positive terminals by a wire of 4 ohms resistance. A third resistance wire of 8 ohms connects middle points of these wires. Draw the circuit diagram. Using Kirchhoff’s laws, find the potential difference at the end of this third wire.
7. Using Kirchoff’s Laws, calculate the value of the electric currents I₁, I₂ and I₃ in the given electrical network.

8. A 24 V battery of internal resistance 1.5 Ω is connected to three coils 18 Ω, 9 Ω and 6 Ω in parallel, a resistor of 4.5 Ω and a reversed battery (emf = 12 V and internal resistance = 3 Ω) as shown. Calculate the

   (I) current in the circuit ,
   (ii) current in resistor of 18 Ω coil and
   (iii) pd across each battery.

   
9. Two cells of emf 1.5 V and 2 V and internal resistance 1 ohm and 2 ohms respectively are connected in parallel to pass a current in the same direction through an external resistance of 5 ohms.
   (a) Draw the circuit diagram.
   (b) Using Kirchhoff’s laws, calculate the current through each branch of the circuit and potential difference across the 5 ohms resistance.

Submitted By Mr.Ashis kumar satapathy
Email Id :[email protected]