Resistors , , and each have resistance . Resistors and are connected in parallel, and…

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

Problem

Resistors

R_1

R_2

, and

R_3

each have resistance

R

. Resistors

R_1

and

R_2

are connected in parallel, and this combination is connected in series with

R_3

, giving an equivalent resistance

R_{\text{eq,1}}

. If

R_3

is replaced by a resistor of resistance

2R

(while

R_1

and

R_2

remain unchanged), the new equivalent resistance is

R_{\text{eq,2}}

. What is the ratio

R_{\text{eq,2}}/R_{\text{eq,1}}

? (a)

\dfrac{4}{3}

(b)

\dfrac{2}{3}

(c)

\dfrac{5}{3}

(d)

\dfrac{3}{2}