Question

In the circuit given below, the value of R is ___________

(a) 2.5 Ω

(b) 5.0 Ω

(c) 7.5 Ω

(d) 10.0 Ω

The question was asked during an online interview.

This intriguing question comes from Series-Series Connection of Two Port Network topic in section Two-Port Networks of Network Theory

Answer 1

Correct option is (c) 7.5 Ω

The explanation is: The resultant R when viewed from voltage source = \(\frac{100}{8}\) = 12.5

∴ R = 12.5 – 10 || 10 = 12.5 – 5 = 7.55 Ω.