Question

Three equal resistances when combined in series are equivalent to 90 ohm. Their equivalent resistance when combined in parallel will be:

• A. 10 ohm
• B. 30 ohm
• C. 270 ohm
• D. 810 ohm

Answer 1

The correct option is A 10 ohm

As per the data,

$R_s$ = $3R$ = $90$ ohm

$\therefore$ $R$ = $30$ ohm

$\frac{1}{R_p}$ = $\frac{3}{R}$

$\therefore$ $\frac{1}{R_p}$ = $\frac{3}{30}$

$\therefore$ $R_p$ = $10ohm$