JEE Advanced2016PhysicsCurrent ElectricityActual
Consider two identical galvanometers and two identical resistors with resistance R. If the internal resistance of the galvanometers R c < R 2 , which of the following statement(s) about any one of the galvanometers is(are) true ?
Options
- AThe maximum voltage range is obtained when all the components are connected in series
- BThe maximum voltage range is obtained when the two resistors and one galvanometer are connected in series, and
- CThe maximum current range is obtained when all the components are connected in parallel
- DThe maximum current range is obtained when the two galvanometers are connected in series and the combination i
Correct answer
B. The maximum voltage range is obtained when the two resistors and one galvanometer are connected in series, and
Step-by-step solution
i = E 2 R + 2 R c V g 1 = i R c = E R c 2 R + R c = E R c 2 R + 2 R c i 2 = E 2 R + R c 2 V g 2 = i 2 2 × R c = 1 2 E 2 R + R c 2 × R c V g 2 = E R c 4 R + R c ....(2) Since R c R 2 2 R c R 2 R + 2 R c 3 R V g 1 > V g 2 i A = E R c Here i = E ( 2 R + 2 R c ) 2 R . 2 R c = E ( R + R c ) 2 R R c i B = 2 R 2 R + 2 R c × E ( R + R c ) 2 R R c = E 2 R c i A > i B