In the fig above, XY is of length 1m, The value of R at balance point Z is
Attached Figure / Diagram
A
3.0Ω
B
13.3Ω
C
15.0Ω
D
30.0Ω
Verified Correct Answer: D.
Physical Principles & Numerical Solution
At null deflection, p.d across R = p.d across xz
p.d across 20\Omega = p.d across zy
\(\frac{R}{20}\) = \(\frac{60}{40}\)
R = 30\Omega
Source: WAEC / JAMB / NECO Classroom Archive (Record #41724)