Question

1. What resistance should be added to two resistors of 8ohm and 5ohm in series respectively, such that
equivalent resistance is 25ohm ?​

Answer 1

Answer:

Resistance of 12Ω should be added to get equivalent resistance as 25Ω.

Explanation:

We know that,

In series combination,

$\implies \bf R_s = R_1 + R_2 + R_3$

$\implies \sf 25 \Omega = 8 \Omega + 5 \Omega + R_3$

$\implies \sf 25 \Omega - R_3 = 13 \Omega$

$\implies \sf -R_3 = 13 \Omega - 25 \Omega$

$\implies \sf -R_3 = -12 \Omega$

$\implies \sf R_3 = 12 \Omega$

$\therefore$ Resistance of 12Ω should be added to get the equivalent resistance of 25Ω.