JEE Advanced | 2014Current Electricity and Electrical InstrumentHard
Question
During an experiment with a metre bridge, the galvanometer shows a null point when the jockey is pressed at 40.0 cm using a standard resistance of 90 Ω, as shown in the figure. The least count of the scale used in the metre bridge is 1 mm. The unknown resistance is
Options
A.60 ± 0.15 Ω
B.135 ± 0.56 Ω
C.60 ± 0.25 Ω
D.135 ± 0.23 Ω
Solution
(Balanced Wheatstone)For R,
⇒ R = 
For ᐃR,
ln R = ln x + ln(100 - x)
ᐃR =
60ᐃR = 0.25 Ω
⇒ R = 60 ± 0.25 Ω
Create a free account to view solution
View Solution FreeTopic: Current Electricity and Electrical Instrument·Practice all Current Electricity and Electrical Instrument questions
More Current Electricity and Electrical Instrument Questions
A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of :...A certain metallic surface is illuminated with monochromatic light of wavelength, λ. The stopping potential for pho...An electrolyte bulb marked 40 W and 200 V, is used in a circuit of supply voltage 100V. Now its power is...The area of the plates of the capacitor shown in figure is S. The dielectric constant and resistivity of the material of...Ratio of equivalent resistance between A and B in two cases will be :-(a) (b)...