A potentiometer circuit is setup as shown. The potential gradient across the potentiometer wire is `k "volt"//cm` and the ammeter present in the circuit reads. `1.0 A` When two-way key is switched off. The balance point, when the key between the terminals (i) 1 and 2 (ii) 1 and 3, is plugged in, are found to be at lengths `l_(2) cm` and `l_(2) cm` respectively. The magnitudes, of the resistors `R` and `X`, in ohm, are then, equal, respectively, to

Options

A. `kl_(1)` and `kl_(2)`
B. `k(l_(1)-l_(1))` and `kl_(2)`
C. `kl_(1)` and `k(l_(2)-l_(1))`
D. `k(l_(2)-l_(1))` and `kl_(1)`

Answer

3

Explanation

`R=kl_(1)` and `R+x=kl_(2)`
`rArrx=kl_(2)-kl_(1)=k(l_(2)-l_(1))`