Q. A resistor of 10 k$\Omega$ having tolerance 10% is connected in series with another resistor of 20$k\Omega$ having tolerance 20%. The tolerance of the combination will be approximately
A) 10%
B) 13%
C) 17%
D) 20%
Explanation
$\mathrm{\Delta}R_{s} = \mathrm{\Delta}R_{1} + \mathrm{\Delta}R_{2} = \left\lbrack \frac{10}{100} \times 10 + \frac{20}{100} \times 20 \right\rbrack k\Omega = 5k\Omega$ $\frac{\Delta R_{s}}{R_{s}} \times 100 = \frac{5}{30} \times 100 = \frac{50}{3} = 17$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.