NEET2008PhysicsCurrent ElectricityActual
A galvanometer having a resistance of 8 is shunted by a wire of resistance 2 . If the total current is 1 A , the part of it passing through the shunt will be
Options
- A0.25 A
- B0.8 A
- C0.2 A
- D0.5 A
Correct answer
B. 0.8 A
Step-by-step solution
Key Idea : Potential difference across galvanometer should be equal to potential difference across shunt. The shunt and galvanometer are connected as shown in figure. Let total current through the parallel combination is i , the current through the galvanometer is i_g and the current through the shunt is i-i_g . The potential difference V_ a b (=V_a-V_b ) is the same for both paths, so array ll & i_g G= (i-i_g ) S or & i_g(G+S)=i S or & i_g i = S S+G array The fraction of current passing through shunt aligned & = i