In the fig above, XY is of length 1m, The value of R at balance point Z is
- 3.0Ω
- 13.3Ω
- 15.0Ω
-
30.0Ω
The correct answer is: D
Explanation
At null deflection, p.d across R = p.d across xz
p.d across 20Ω = p.d across zy
\(\frac{R}{20}\) = \(\frac{60}{40}\)
R = 30Ω