Question

0.7 Derive the expression for net resistance in series combination.​

Answer 1

Answer:

If a number of resistors are joined together so that the current flowing across each resistor is the same, then the resistances are said to be connected in series.

As shown in Fig, consider three resistances R1, R2 and R3 connected in series,

Suppose a current I flows through the circuit when a cell of voltage V is connected across the combination.

Using Ohm's law, potential differences across the three resistances will be,

V1 = R1, V2 = IR2, V3 = IR3

Let, Rs be the equivalent resistance of the

combination

Therefore,

V = IR

But, V = V1 + V2 + V3

: IR = IR1 + IR2 + IR3

That is,

R=R1+ R2+ R3