Two resistors of 6 ohm and 3 ohm are connected in parallel. What is the effective resistance of the combination?

1. For parallel: $\dfrac{1}{R_p} = \dfrac{1}{R_1} + \dfrac{1}{R_2}$. 2. $\dfrac{1}{R_p} = \dfrac{1}{6} + \dfrac{1}{3} = \dfrac{1}{6} + \dfrac{2}{6} = \dfrac{3}{6}$. 3. So $R_p = 2\,\Omega$. 4. The value 9 is the series sum, not parallel; parallel must be less than the smaller resistor. _Source: Samacheer Kalvi (TN SCERT) Class 10 Science, Unit 4 Electricity "Electricity", p.62_