InterviewSolution
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InterviewSolution
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In figure circuit section `AB` absorbs energy at the rate of `5.0 W` when a current` i =1.0A` passes through it in the indicated direction.(a) What is the potential difference between points `A` and `B`? (b) Emf device `X` does not have internal resistance. What is its emf? (c) What is its polarity (the orientation of its positive and negative terminals)? A. `24 V`B. `32 V`C. 48 V`D. `12 V` |
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Answer» Correct Answer - C As section `AB` consumes `50 W at 1 A and P = VI`. S0 `V = V_(A) - V_(B) = (P)/(I) = (50)/(1) (W)/(A) = 50 V` As `R and C` are in series, `V = V_(R) + V_( C ) or V_( C ) = V - V_(R )` But here `V = 50 V and V_(R) = IR = 1 xx 2 = 2 V`. So `V_( C ) = 50 - 2 = 48 V`. Now as the element `C` absorbs energy and has no resistance , it is a source of emf with zero internal resistance ( i.e., ideal battery ). So emf is `E = V + Ir = 48 + 1 xx 0 = 48 V`. As in charging , positive and negative terminals of the charger are connected to the positive and negative terminals of the battery, respectively ,` B` is connected to the negative terminal of element `C`. |
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