In the fig above, XY is of length 1m, The value of R at b...
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
Correct answer is D
At null deflection, p.d across R = p.d across xz
p.d across 20Ω = p.d across zy
R20 = 6040
R = 30Ω