Which of the following expressions correctly gives the equivalent resistance of two…

PHYSICS · Single correct · A Level · Physics · Electricity · Electricity

Problem

Which of the following expressions correctly gives the equivalent resistance

R_{\text{eq}}

of two resistors

R_1

and

R_2

connected in parallel? (a)

R_{\text{eq}} = R_1 + R_2

(b)

\dfrac{1}{R_{\text{eq}}} = \dfrac{1}{R_1} + \dfrac{1}{R_2}

(c)

R_{\text{eq}} = \sqrt{R_1 R_2}

(d)

\dfrac{1}{R_{\text{eq}}} = \dfrac{1}{2}\left(\dfrac{1}{R_1}+\dfrac{1}{R_2}\right)