Equivalent Resistance — Prelims Questions

Three resistors of $2,\Omega$, $3,\Omega$, and $5,\Omega$ are connected in series. What is their equivalent resistance?

Two resistors, $R_1 = 6,\Omega$ and $R_2 = 3,\Omega$, are connected in parallel. What is their equivalent resistance?

A $4,\Omega$ resistor is connected in series with a parallel combination of two $8,\Omega$ resistors. What is the equivalent resistance of the entire circuit?

A circuit consists of a $10,\Omega$ resistor, a $20,\Omega$ resistor, and a $30,\Omega$ resistor connected in parallel. What is the equivalent resistance?

Consider a circuit where a $5,\Omega$ resistor is connected in series with a parallel combination of a $10,\Omega$ resistor and a $15,\Omega$ resistor. What is the total equivalent resistance?

Which of the following statements about equivalent resistance is INCORRECT?