Neco 2020 Physics Question 21
Practice objective / multiple choice question 21 from the 2020 Neco Physics examination.
An ideal battery of emf \(E\) V and internal resistance \(r\) \(\Omega\) is connected to a load resistor \(R\) \(\Omega\). When \(R = 6\,\Omega\) the terminal voltage is \(12\,\text{V}\) and the efficiency of the circuit (ratio of power delivered to the load to the total chemical power) is \(60\%\). The battery is then re‑connected to a different load resistor \(R'\) \(\Omega\) such that the efficiency becomes \(80\%\). Find the value of \(R'\) in ohms.
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About This Question
This is Neco 2020 Physics Question 21. It is one of the objective questions from the 2020 Neco Physics examination.
Difficulty level: Hard .
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