Two metal wires of identical dimensions are connected in series- If -1 and -2 are the conductivities of the metals respectively- the effective conductivity of the combination is-

The correct option is D σ_1σ_2σ_1+σ_2 R=R_1+R_2 ρ lA=ρ_1 lA+ρ_2 lA ρ=ρ_1+ρ_2 1σ=1σ_1+1σ_2 σ=σ_1σ_2σ_1+σ_2 ...

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Standard XII

Physics

Idea of Temperature

Two metal wir...

Question

Two metal wires of identical dimensions are connected in series. If $σ_{1}$ and $σ_{2}$ are the conductivities of the metals respectively, the effective conductivity of the combination is?

σ_{1} + σ_{2}

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\frac{σ_{1} + σ_{2}}{2}

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\sqrt{σ_{1} σ_{2}}

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\frac{σ_{1} σ_{2}}{σ_{1} + σ_{2}}

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Solution

The correct option is D $\frac{σ_{1} σ_{2}}{σ_{1} + σ_{2}}$
$R = R_{1} + R_{2} \frac{ρ l}{A} = \frac{ρ_{1} l}{A} + \frac{ρ_{2} l}{A} ρ = ρ_{1} + ρ_{2} \frac{1}{σ} = \frac{1}{σ_{1}} + \frac{1}{σ_{2}} σ = \frac{σ_{1} σ_{2}}{σ_{1} + σ_{2}}$

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Two metal wires of identical dimensions are connected in series. If σ1 and σ2 are the conductivities of the metals respectively, the effective conductivity of the combination is?

The correct option is D σ1σ2σ1+σ2R=R1+R2ρlA=ρ1lA+ρ2lAρ=ρ1+ρ21σ=1σ1+1σ2σ=σ1σ2σ1+σ2

Two metal wires of identical dimensions are connected in series. If $σ_{1}$ and $σ_{2}$ are the conductivities of the metals respectively, the effective conductivity of the combination is?

The correct option is D $\frac{σ_{1} σ_{2}}{σ_{1} + σ_{2}}$
$R = R_{1} + R_{2} \frac{ρ l}{A} = \frac{ρ_{1} l}{A} + \frac{ρ_{2} l}{A} ρ = ρ_{1} + ρ_{2} \frac{1}{σ} = \frac{1}{σ_{1}} + \frac{1}{σ_{2}} σ = \frac{σ_{1} σ_{2}}{σ_{1} + σ_{2}}$