The effective resistance of two resistors in parallel is $\frac{12}{7}\text{\hspace{0.17em}\hspace{0.17em}}\Omega$. If one of the resistors is disconnected the resistance becomes 4 Ω. The resistance of the other resistor is

(1) 4 Ω

(2) 3 Ω

(3) $\frac{12}{7}\text{\hspace{0.17em}\hspace{0.17em}}\Omega$

(4) $\frac{7}{12}\Omega$

(2) $\frac{7}{12}=\frac{1}{4}+\frac{1}{R}\text{\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}}⇒\text{\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}}R=3\Omega$

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