Question

What is the equivalent resistance of series combination of 3 resistors?

(a) Rs = R1 + R2 + R3

(b) Rs = \(\frac {1}{(R_1 + R_2 + R_3 )}\)

(c) Rs = \(\frac {1}{R_1} + \frac {1}{R_2} + \frac {1}{R_3}\)

(d) Rs = \(\frac {(R_1 + R_2)}{R_3}\)

I got this question in unit test.

Enquiry is from Combination of Resistors topic in portion Current Electricity of Physics – Class 12

Answer 1

Correct choice is (a) Rs = R1 + R2 + R3

For explanation I would say: When three resistors are connected in series, then the equivalent resistance of this combination is Rs = R1 + R2 + R3. So, if 3 resistors having resistances 10, 15, and 20 ohms, are connected in series, then equivalent resistance of this combination is Rs = 10+15+20 = 45 ohms.