PEE-11

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Explain what is series circuit ?

Ans.

     The circuit in which resistances are joined or connected end to end so that there is only one path for current flowing is called a series circuit.

Consider three resistance R₁, R₂ & R₃ ohms connected in series across a battery of V volt as shown in figure(i). 

    Obviously there is only one path for current I i.e., current is same throughout the circuit. By ohms law, voltage across the various resistance is………..

V₁ = IR₁ ;         V₂ = IR₂  ;        V₃ = IR₃

Now,

     V = V₁ + V₂ + V₃

     V = IR₁ + IR₂ + IR₃

     V = I ( R₁ + R₂ + R₃ )

 V/I = R₁ + R₂ + R₃

     But,   V/I   is the total resistance Rт between points A & B. Rт is called the total or equivalent resistance of the three resistances.

     So total resistance,  Rт =  R₁ + R₂ + R₃

     Hence, when a number of resistances are connected in series, the total resistance is equal to the sum of individual resistances.