Physics

Problem

![](https://storage.googleapis.com/diraq-contents/question-bank/question-images/b82d85700a35/2025_11_20_7a5c057bd37ecaad0ec9g-13.jpg) 79. Four resistors,

R_{1}, R_{2}, R_{3}

, and

R_{4}

, are connected in the circuit diagram above. When the switch is closed, current flows in the circuit. If no current flows through the ammeter when it is connected as shown, what would be the value of

R_{3}

? (A)

\frac{R_{1}+R_{4}}{\left(R_{1}+R_{2}\right)\left(R_{3}+R_{4}\right)}

(B)

\frac{\left(R_{1}+R_{2}\right)\left(R_{4}\right)}{\left(R_{2}+R_{4}\right)}

(C)

\frac{R_{1}+R_{2}}{R_{4}}

(D)

R_{1} \frac{R_{4}}{R_{2}}

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