Question

If σ1, σ2, and σ3 are the conductances of three conductor then equivalent conductance when they are joined in series, will be.

(A) σ1 + σ2 + σ3

(B) (1/σ1) + (1/σ2) + (1/σ3)

(C) {(σ1σ2σ3)/(σ1 + σ2 + σ3)}

(D) of these.

Answer 1

The correct option (B) (1/σ1) + (1/σ2) + (1/σ3)

Explanation:

in series, Reflective = R1 + R2 + R3

As conductance = {1/(Resistance)}

∴ conductance effective = (1/σ1) + (1/σ2) + (1/σ3)

i.e. {1/σeff} = (1/σ1) + (1/σ2) + (1/σ3)