Consider two identical galvanometers and two identical resistors with resistance `R`. If the internal resistance of the galvanometers `R_(c) lt R//2`, which of the following statement(s) about any one of the galvanometers is (are) true?

Options

A. The maximum voltage range is obtained when the two resistors and one galvanometer are connected in series
B. The maximum voltage range is obtained when the two resistors and one galvanometer are connected in series , and the second galvanometer is connected in parallel to the first galvanometer
C. The maximum current range is obtained when all the components are connected in parallel
D. The maximum current range is obtained when the two galvanometers are connected in series and the combination is connected in parallel with both the resistors

Answer

A, C

Explanation

The range of voltmeter `V` is given by the experession
` V = I_(g) [R_(c) + (R_(c)+R+R)]`
`V` is max inthis case as `RHS` is maximum. Thus (a) is correct.
The range of ammeter `I` is given by the expression ` I = (I_(g) R_(c))/(R_(eq))+I_(g)` Where ` (1)/(R_(eq)) = (1)/(R_(c))+(1)/(R)`
Here `R_(eq)` is minimum and therefore `I~ is maximum. Thus(c) is the correct option.