AP EAMCET201726 Apr 2017Morning ShiftPhysicsCurrent ElectricityActual
In the determination of the internal resistance of a cell with a potentiometer, the error in the measurement of the balancing length is 1 ~mm . When the cell alone is connected in the circuit, the balancing length is obtained at 60 ~cm and when the cell is shunted with a resistance of 10 2 % , the balancing length is obtained at 50 ~cm . The error in the determination of the internal resistance of the cell is
Options
- A2.4 %
- B4.2 %
- C1.8 %
- D5.6 %
Correct answer
B. 4.2 %
Step-by-step solution
r=R ( l₁ l₂ -1 ) This is value of internal resistance here. aligned & r r 100= R R 100+ ( l₁ l₂ ) ( l₁ l₂ ) 100 & =4+0.2=4.2 % aligned