JEE Main2014PhysicsCurrent ElectricityActual
In the experiment of calibration of voltmeter, a standard cell of e.m.f. 1.1 volt is balanced against 440 ~cm of potential wire. The potential difference across the ends of resistance is found to balance against 220 ~cm of the wire. The corresponding reading of voltmeter is 0.5 volt. The error in the reading of volmeter will be:
Options
- A-0.15 volt
- B0.15 volt
- C0.5 volt
- D-0.05 volt
Correct answer
D. -0.05 volt
Step-by-step solution
In a voltmeter gathered V l ~V = k l gathered Now, it is given E =1.1 volt for l₁=440 ~cm and V =0.5 volt for l₂=220 ~cm Let the error in reading of voltmeter be V then, aligned &1.1=400 ~K and (0.5- V )=220 ~K . & 1.1 440 = 0.5- V 220 & V =-0.05 volt aligned