In a meter bridge, the left and right gaps are closed by resistances 2  ohm and 3  ohm respectively.  The value of shunt to be connected to 3  ohm resistor to shift the balancing point by 22.5 cm is

Resistance R=2 Ω Resistance S=3 Ω Balancing length l 1=22.5 cm Balancing condition for meter bridge RS=l100−l 23=l100−l ⇒l=40cm shunt to be connected to 3 ohm resistorRS=l 1100−l 1 23X3+X=62.537.5 18+6X=15X ⇒9X=18    ∴  X=2 Ω