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In a circuit shown in figure if the internal resistance of the sources are negligible then at what value of resistance `R` will the thermal power generated in it be the maximum. What is its value in ohms ? |
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Answer» Equivalent emf of the circuit across, `AB` is given by `E_(eq)(2)/(3) xx 4V` Equivalnet resistance `rArr (1)/(r_(eq))=(1)/(3)+(1)/(6)rArrr_(eq)=2Omega` Now, we have Current `I=(10-4)/(2+R)=(6)/(2+R)` `:. ` Power dissipated in R `P=i^(2)R=(36R)/((2+R)^(2))` for `P` to be maximum. `(dP)/(dR)=36[((2+R)^(2)-R(2)(2+R))/((2+R)^(2))]=0` `R=2Omega` |
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